>> lou: from hollywood, it's "jimmy kimmel live" with guest host mark rober. tonight, demi lovato and science bob pflugfelder. with cleto and the cletones. and now, mark rober! [ cheers and applause ] ♪ >> mark: wow! wow, wow! wow! thank you! thank you, okay, okay. this is great. welcome to "jimmy kimmel live"! [ cheers and applause ]

all right. thank you for clapping even though most of you have no idea who i am. [ laughter ] guillermo, do you even know who i am? >> guillermo: you're the guy from the internet, right? [ laughter ] >> mark: that's good enough, i'll take it. my name is mark rober. i'm an engineer. [ cheers and applause ] i worked at nasa for nine years helping with the mars rover. i worked at apple for four years designing products. now i have a youtube channel. which sounds a little like i traded a tesla for a pair of rollerblades. [ laughter ] but i love it. i make videos that combine science, engineering, and pranks. and at this point, the channel has over 22 million subscribers. [ cheers and applause ] here's a little sampling of what i do.

>> this guy took a package from my porch. what he doesn't know is this is a custom-built bait package that is recording him on four different cameras and it's about to unleash a pound of the world's finest glitter along with other surprises. >> surprise, mother [ bleep ]! ♪ ♪ >> everything in my life is my attempt at making a squirrel video. this is the world's first-ever actual pool of jell-o. hit it! >> you built a very powerful t-shirt cannon. ♪ >> i'm in a cage!

>> oh my gosh. oh! [ cheers and applause ] >> mark: by the way, do not, do not try that last one at home or anywhere, really, because you will go to jail. [ laughter ] a majority of my fans are ages 5 to 25, and they're usually pretty punked to meet me. anyone older than that assumes i'm a cashier at the gap. [ laughter ] i wanted to conduct an experiment. we went to the farmers' market in l.a. to talk to people of all ages to see who would recognize me and who would not. >> what's up, guys? you know who i am? >> i know. >> who am i? >> you're a scientist on youtube. >> what's my name? >> mark rober. >> this is mark rober. >> mark rober! hee hee! >> do you know who i am? >> yes. >> grandpa? do you know who i am? >> no.

>> do you know who i am? >> no. >> not actually. >> not actually, okay. >> no, i do not. >> based on how i look, what would you guess my occupation is? >> an assistant? >> accountant? >> barnes & noble? >> a service guy at the farmers' market? >> a service guy. >> skateboarder. >> maybe you work in a bookstore. >> a bookstore? like barnes & noble? >> like barnes & noble. >> i'll give you a clue. glitter. fart spray. no? the fart spray didn't do it? i punish people sometimes who don't do the right thing. >> a teacher? >> a teacher. yeah. what kind of school did you go to? toothpaste is a clue. if i say squirrel, that's a dead give-away. >> you're into bdsm? [ laughter ] >> squirrel? the biggest hint, my name is mark rober.

>> who's mark rober? >> who's mark roper? >> rober with a "b." >> okay. >> do you have your phone? >> i do. >> let's call one of your kids. >> hey, trent. >> what's up, trent? >> oh! >> can you give her a hint who i am? she didn't know who i was. >> you're the guy that does all the science experiments and things. >> there you go. >> this is mark rober. >> and go, "youtube superstar sensation." >> he's probably the most famous person that i know. >> he's an engineer who has a youtube channel. >> do you have a lot of watchers? >> i do. do i have a lot of watchers? >> yes. >> if you had to guess how many watchers i do have, what would you think? >> 10,000? >> 10,000. 22 million subscribers. >> oh my god. >> so -- i'm kind of a big deal. [ laughter ] >> okay. >> have you heard of jimmy kimmel? >> yes, i've heard of jimmy kimmel. >> who do you think is more famous, mark rober or jimmy kimmel? >> jimmy kimmel. >> yeah.

because you don't know who mark rober is, do you? >> no, i don't. >> okay. [ cheers and applause ] >> mark: so while this is my first time hosting a talk show, i've actually been working on a really fun series called "the revengineers" which is coming to discovery this fall. on the show my crew and i use engineering to make the world a better place by punishing troublemakers who violate social norms. for example, if someone doesn't return their shopping cart, we make an army of remote-controlled shopping carts to chase them down. [ laughter ] [ cheers and applause ] yeah. it gets better, it gets better. because if they don't pick up their dog's poop, we build an autonomous robot dog to launch it back at them. [ cheers and applause ] this needs to be done. this is a service that needs to happen. but just like on my show, i like rewarding people who do the right thing. and i wanted to do that while i was hosting tonight because honestly, people doing the right

thing is rare, especially here on hollywood boulevard. [ laughter ] so we set up some ridiculous situations on the sidewalk in front of the theater here where various people who needed assistance could see if any good samaritans would stop to lend a hand. in this first one, we set it up where we have a kid giving out free carrot samples and we told him that he pretend dropping his mom's phone in a giant vat of ranch dressing. do you think anyone reaches in to help him grab it? let's find out. >> oh, man, i forgot something in my car. here. jackson, i'm trusting you. anything happens, call me, okay? this is my other phone. >> i will. >> see you later. >> all right. oh! oh, shoot. can you please help me get this -- sir, sir, can you please help me? i just dropped my mom's phone in this bucket of ranch. >> ha ha! >> no.

sir, sir, please? >> i'm good, man. >> sir, vacation guy, can you please help me? i dropped my phone in here. i dropped my phone in here, come on, man. i know you can hear me, come on. >> are these free samples? >> i just dropped my mom's phone in here and i need help. can you please help me? >> you want me to get it? >> yeah, are your hands clean? >> okay, okay. >> dude, thank you so much. >> you're okay. >> it's cool. >> isn't it creamy? you're a really good samaritan. have a great day, mister. [ cheers and applause ] >> mark: okay, so in this next one, we had a guy walking around with a giant fish, trying to get someone to hold it for him so he could answer his phone. how about this one? what do you guys think? is someone going to help him? it's a big fish, let's see.

>> could one of you hold this fish? i've got to get this call real quick. do you want to hold the fish? please, please, can you help me out here for one second? just -- i'm sorry -- >> [ bleep ] off. >> that is a hard no, okay. hey, guys. can you -- you don't eat fish? i don't need you to eat fish, i need you to hold this. does anyone have arms? does anyone have a soul? can you hold this fish just for a second? just for one second. here you go, okay. thank you so much. honey? yeah? one sec, stay right there. he said what? triplets? i'm going to be a dad! i'm going to have triplets, i'm going to have triplets! oh my god. i'm going to get you some chocolates, hold on one second here, hold on. oh my god, oh my god, oh god. hold on. i want to get some cigars. hold on. i'm going to be a dad.

>> congratulations. >> i'm going to be a dad, oh my god! oh! oh, a picture? [ cheers and applause ] >> mark: all right. should we do one more? [ cheers ] that's a good choice. i think this one's my favorite. we have one of those sign spinner guys, you see them outside of the stores. he was dressed as a penguin and he really needed to use the bathroom so he asked someone to fill in for him. while he went and did his business. this is how it went. >> i've really got to use the bathroom. sir, sir, could you help me? i -- all right. good talking. man oh man, do i need to need to use the bathroom. excuse me, could you help me out? i just need to use the bathroom. bro. hi. i really got to use the bathroom. >> bathroom? >> yeah, if my boss comes out and sees i'm not in the penguin costume, he's going to be really mad. can you put on -- just for a minute, i'll be really fast.

>> it smells bad? >> no, brand-new. >> how much time? >> like two minutes? i'll be fast. >> okay. >> oh, awesome, thank you so much. >> what do you want me to do first? >> actually, unzip me. ♪ >> if my boss comes by, his name is terry. >> terry. >> and just tell him he has really nice hair. >> hair. okay. >> just try and spin the sign while you're here. okay, great. thank you so much. i'll be right back. ♪ [ applause ] ♪ ♪ ♪ ♪

>> what are you doing? dance, you've got to dance more. i hired you to spin the sign, spin it. i paid for spinning lessons for you, spin the sign. and dance. >> okay. i like your hair. >> oh, thank you, thank you. thanks. yeah, i just had it done, thanks for noticing. dance and spin, dance and spin! thank you. up believable. ♪ [ applause ] >> thank you so much. oh, no! what happened? >> sing, dance, dancing. dance, dancing. >> was your dancing not good enough? >> no, he likes it. i say, i like your hair. he said, okay. he went away. everything is okay. >> oh, good. thank you. thank you so much. i appreciate it. [ cheers and applause ] >> mark: all right! we actually have all three of our good samaritans in the audience with us tonight. [ cheers and applause ] and you guys don't know this yet. but i'm about to potentially reward you for your act of kindness. come here, follow me over here.

[ cheers and applause ] stand right here. okay. so name-wise, what have we got? >> henne, kevin, but i go by henne. >> menachem. >> samantha. >> mark: okay. here's the deal, you guys. right now i'm going to give you guys a chance to win some money. because i'm hosting the show, we're doing this mark rober style, which means we've got to use some explosives. [ cheers and applause ] these are the explosives. so as you can see over here, there's three items. they're covered up. all right, guillermo. unveil the first one. that is a bowl of nachos. [ cheers and applause ] okay? the second one is a wedding cake. [ cheers and applause ] and the third one is a

watermelon that says $15,000. [ cheers and applause ] that's a clue. i'm going to explain why in a second. you've got detonators here. each one is connected to each of those items over there. the thing is we've got this jumble of wires here. you don't know which goes to which. does that make sense? here's the challenge. the three of you guys have to work together. you have to pick which detonator you want to push. if you blow up the cake or the nachos, your prize will be blown-up cake or nachos. not that amazing. if you blow up that watermelon, the three of you are going to split $15,000. [ cheers and applause ] i'm basically oprah at this point. that $15,000, i might add, was previously owned by jimmy kimmel. [ cheers and applause ] i found it while i was looking through his desk. you guys understand the rules? okay. so the audience is going to count down from ten, then they

get to one, you have to have made your choice and detonate it. if you get the watermelon, you get $15,000. 10 seconds on the clock. audience, it's going to be loud, you might want to plug your ears. here we go. ten, nine, eight, seven, six, five, four -- you've got to choose. this one? this one? [ cheers and applause ] you did it! oh, man! you did it! this is amazing. [ cheers and applause ] all right, you guys are going to split $15,000. congratulations to you. on top of that, i actually have one more surprise for you guys. which in my opinion honestly is better than the money. because i'm going to let you

blow up the cake and the nachos anyway. do that one. do that one. [ cheers and applause ] all right! we have an amazing show for you tonight. my friend science bob pflugfelder is here. we're going to play a huge prank i promise you do not want to miss. we'll be right back with demi lovato, so stick around. [ cheers and applause ] ♪ ♪ [dog barks] [dog panting] [dogs barking] [dogs growling] [dogs whimpering] (vo) the subaru crosstrek. dog tested. dog approved.

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♪♪♪ ♪♪ ♪♪ [ cheers and applause ] ♪ >> mark: welcome back to "jimmy kimmel live." i'm mark rober. tonight my friend science bob pflugfelder is here. later we're going to pull a prank that is going to cause so much damage, you're going to have to see it to believe it.

it is a banger. and please make sure to watch "jimmy kimmel live" next week with hosts dana carvey, rupaul, kerry washington and guests. [ cheers and applause ] our first guest is a talented musical artist with a brand-new album i can't actually say on television. [ cheers and applause ] it's called "holy f" and it comes out august 19th. please welcome demi lovato! [ cheers and applause ] ♪ >> mark: welcome to the show. >> thank you. >> mark: so first of all, i heard you had an accident yesterday. what the holy "f" happened?

>> i was picking something up off the floor that i dropped. i'm a huge fan of crystals. i have literally an amethyst that is about this tall. >> mark: and sharp, i assume? >> it's just really heavy and the pieces are sharp. anyways, i went down to pick something up and i didn't see the amethyst, and i hit my head. and i had to get three stitches last night. [ audience moaning ] in my face. and i called my doctor, "i hit my face, do i need stitches?" he was like, "facetime me." we facetimed and i'm like, "i have kimmel tomorrow." [ laughter ] what do i do? i made a tiktok before i even showed up. >> mark: that's actually how i heard about it. [ applause ] thank you for pushing through. this is impressive that you're here. your new album comes out next month right before your 30th birthday, right? >> yes. [ cheers and applause ] the day before.

>> mark: the day before. and you're also going on tour. i listened to some of the songs. it's very rock 'n' roll. it feels like this would be really fun to perform, right? >> yes, definitely. i'm so excited. i'm going back to my roots. when i started making music in this industry, it was pop-rock. and i was a huge fan of the warped tour days and all that stuff. [ cheers and applause ] i'm just going back to that. >> mark: yeah. that's the best. like, when i want to really jam and rock out, it's like the early 2000 stuff. >> yes. >> mark: you put on those rock ballads that you sing along to. >> totally. >> mark: i feel that with these new songs. >> thanks. >> mark: this is amazing. i know -- it's actually been four years since you've been on tour? >> yes, it has. >> mark: you filmed a tv show. >> i did. >> mark: about aliens. >> i did, yes. >> mark: now you're kind of in my wheelhouse, i worked at nasa for nine years. >> i have to ask you, what do you know? [ laughter ]

>> mark: i mean, just between you and me? >> just between us. >> mark: not on national television? >> not on national television. >> mark: i worked in pasadena, not area 51. [ laughter ] i will say this, i think what you and i -- you believe aliens exist, so do i. by the way, most of the scientific community does. >> yeah. >> mark: it would be really crazy with the amount of stars and planets out there -- >> yes. >> mark: there's more stars than there are grains of sand on the entire ocean floors. to think we're the only life is kind of bonkers. >> i'm right there with you. >> mark: you're with me? >> i'm with you, yeah. >> mark: do you feel like you see stuff in the sky? >> i have seen stuff. >> mark: that was part of the show, right? >> yes, that was part of the show. i've also had really incredible experiences after, like, meditating in the desert. you see stuff appear and it's like -- it blows your mind. it kind of shatters your reality for a second. then you're like, wow, this universe is so big. you feel, like, so little. but also, like, we have so much

meaning. >> mark: like connected. >> yeah. >> mark: some of those experiences, that influenced the music on this album? >> no. [ laughter ] >> mark: perfect. >> this is all about rock 'n' roll. >> mark: just rock 'n' roll, okay. >> a lot of -- yeah. >> mark: i love it. [ laughter ] >> you'll have to listen. >> mark: yeah. you'll have to listen. [ cheers and applause ] it's great. i mean, you've had experiences with rock 'n' roll. you yourself. i think there's a story, you've been in mosh pits and had to navigate your way out of mosh pits, right? >> yes. there was this -- there was this band called dimmu borgir. i went to their show. they were like a norwegian black metal band or something. and i was at the show. and i just happened to be in the center where the mosh pit happens. but everyone, they were like grown men, and i was this 14-year-old girl. so i had to, like, con my way out and crowd surf to the front of the stage. >> mark: amazing. >> i lost my shoe. it was a great time. [ laughter ] >> mark: wow. >> yeah. >> mark: that's a -- i'm the engineer here but that's a power

move, that's invention right there, getting up and over. >> thank you. nasa is my next stop. [ laughter ] >> mark: your next stop, okay. amazing. well, that's good. after the break, we're going to kind of do -- i've actually always wanted to be a musical artist. i invented a machine that's going to kind of help me. i'm hoping you'll do kind of a duet with me. are you willing? >> yeah, i'm willing. >> mark: all right. [ cheers and applause ] when we come back, we've got more with demi lovato! ♪ ♪ to everyone still crushing it

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the new xfinity supersonic bundle. it's kind of a big deal. [ cheers and applause ] >> mark: welcome back. i am here with demi lovato. science bob is coming up. [ cheers and applause ] demi was gracious enough to do me a solid, because demi, at this point i've been the bit guy on kimmel, i've been on the couch to be interviewed, i've now been the host. what jimmy would never allow me to be is the musical guest. there's a good reason for that, because i have no musical talent. but i am an engineer, so i've built something to kind of help me be a good musical guest.

so that's what we see here. >> it's so impressive, by the way. >> mark: that's a little premature, i haven't turned it on yet. [ laughter ] i'm going to turn it on. and then what's going to happen -- this train's going to go around. might be a melody you might recognize. the train's hitting the glass. that sound a little familiar? >> yeah, a little bit. >> mark: all right, you want to hum along? maybe start to get a feel for it. i'm going to add the snare drum. ♪ ♪ uh-huh what's wrong with me what's wrong with being ♪ ♪ uh-huh what's wrong with being what's wrong with being what's wrong with being confident ♪ ♪ uh-huh hey hey ♪ >> mark: one more. >> okay.

♪ oh what's wrong with being confident ♪ [ cheers and applause ] >> mark: yes! could i do it? >> we did it. >> mark: yes! [ cheers and applause ] all right, thank you so much, demi. "holy f" comes out on august 19th. we'll be right back with science bob! announcer: type 2 diabetes? discover the power of 3 in the ozempic® tri-zone. in my ozempic® tri-zone, i lowered my a1c, cv risk, and lost some weight. announcer: ozempic® provides powerful a1c reduction. in studies, the majority of people reached an a1c under 7 and maintained it. ozempic® lowers the risk of major cardiovascular events such as stroke, heart attack, or death in adults also with known heart disease. and you may lose weight. adults lost up to 14 pounds.

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[ cheers and applause ] >> mark: welcome back. our next guest is a real-life science teacher from massachusetts who loves explosions just as much as i do. he's an author, too. the first book in his series for kids is "nick and tesla's high-voltage danger lab." please welcome my good friend science bob pflugfelder! [ cheers and applause ] >> what is jimmy thinking? >> mark: what was jimmy thinking? leaving this place to the nerds. [ laughter ] all right, bob. so this is actually a pretty cool book. >> yeah, yeah. >> mark: i read some of it. the kids come up with contraptions, then you show them how to build them? >> yeah, yeah. if your kids are a fan of what mark and i do, this is definitely in their alley. and worth checking out, i think. >> mark: all right. speaking of in our alley, what the heck do we have here? >> we had some hollywood explosions earlier in the show, i figured let's do some real explosions. [ cheers and applause ]

>> mark: by the way, bob, i just want to say, jimmy's not here. you can use the big words today. [ laughter ] >> oh, yeah, nice, okay. excellent. all right, so what we have here is an actual ostrich egg. and what we're going to do is fill this with the world's most dangerous beach ball. this is not filled with air, this is filled with hydrogen. >> mark: oh! >> yeah. you've got an amazing rover on mars. that went up on the atlas v rocket, i believe. >> mark: yep. >> and what do those use for fuel? >> mark: i believe hydrogen and oxygen. >> excellent. there's a hole in the bottom, a hole in the top. i'm going to put this nozzle here. we're going to purge the air out of this, fill the whole thing entirely with hydrogen. that is half of our rocket fuel. >> mark: wow. and you're having me hold it. [ laughter ] >> once it is entirely purged of the air, then i'm going to ignite it in our boom box here. >> mark: okay. >> like a candle, right? again, it's all hydrogen.

it's going to burn pretty clean. hydrogen is a pretty clean-burning fuel. all right, let's seal this one up. and get that out of the way. we don't want that -- >> mark: that's a clever fill mechanism, by the way. >> thank you, works perfectly. >> mark: the kind of details jimmy wouldn't notice, i feel like. [ laughter ] >> i'm going to light this. it's going too hopefully burn nice and cleanly. you might not even see the flame. as it burns, the oxygen is going to come in. that's the oxygen part. if all goes well, it's going to turn into rocket fuel and we'll get to see what happens. you ready? here we go. we light that. now it's burning. i can barely see it. the oxygen is coming. come on over. >> mark: okay, okay. >> all right, so now the oxygen is coming in while the flame burns. very clean, very zen-like, very calm. but we do get to a point where we get two parts hydrogen, one part oxygen. >> mark: oh! [ cheers and applause ] >> that happens, yeah. not much after that. yeah.

>> mark: oh! >> all right, so -- >> mark: wow, i did not make that look cool. [ laughter ] >> all right, you guys want more fire? [ cheers and applause ] >> mark: yes. >> we've got to give the people what they want. >> mark: we've got to give the people what they want. >> there's a classic classroom demonstration where you take one of those five-gallon plastic water bottles, pour some ethanol fuel in it, and throw a match in there, you get this nice whoosh of fire. science is all about variables. i've changed the variable up. instead of that plastic bottle, i'm going to use this long tube. >> mark: cool. >> this is our ethanol fuel, biofuel. i'm going to pour that in here. if you'll get the other end. >> mark: sure. >> what we're going to do, we're going to tip this over. you genuinely have not seen these before? >> mark: i genuinely have not. i demanded i didn't want to see it. >> this is going to be fun. >> mark: honest reactions. >> dump that. so we need to use evaporation for this. >> mark: okay. by the way, jimmy, evaporation? that's when the liquidy stuff

goes to gas stuff. [ laughter ] okay? i know you're watching at home. >> all right. there we go. all right, so now we've evaporated. there's some nice vapor in there. i'm going to have you step up on here. >> mark: just look down the bottom? >> yeah, well, not quite. put that glove on, that's a fire-resistant glove. i'm going to light this match. i'll lift the top off, you're going to drop that in there. >> mark: like quickly? >> yeah, kind of drop it in. we'll see what happens when we evaporate -- maybe bring the lights down a little bit for this. all right, here we go. light this first. all right, there it is. you ready? >> mark: i'm ready. >> go. >> mark: yah! wow! >> fun, huh? [ applause ] >> mark: yeah! >> it shot the thing out. that's good. >> mark: okay, this one looks bigger. >> that's it, we're just increasing the variable. bigger, better, television, here we go. >> mark: this is why we're friends, bob. >> that's right, man, we know how to party. >> mark: yep. [ laughter ]

>> all right, here we go. there you go. hold on to that. >> mark: here we go. >> that goes on there. there we go. >> mark: okay. i'll be faster this time. >> three, two, one. whoa! yes! [ cheers and applause ] >> all right, beautiful. >> mark: you see the little trail going down too. >> the beauty of science. >> mark: okay. >> so mark, we have bonded over one particular experiment. >> mark: that's right. elephant toothpaste. >> elephant's toothpaste, yeah. look at that. this was actually the very first experiment i ever did. i think it was 21 visits ago. >> mark: yep. >> this was the very first experiment we did. and you and i have done this in incredible levels of it. let's show the fun people what we've got here. >> mark: okay. >> we have hydrogen peroxide. a catalyst. we've got some soap. a little food coloring. >> mark: potassium iodine, jimmy wouldn't know that. >> position reaction, and -- hey! [ cheers and applause ]

what's not to love about that? >> mark: we put in a little extra because jimmy's not here. >> yeah. >> mark: all right. >> all right. so that's some beautiful chemistry. >> mark: okay. >> but you had another idea? >> mark: yeah. sorry, jimmy. >> all right, jimmy. >> mark: all right, speaking of jimmy. so one thing we haven't tried, bob, is like, we've done all sorts of -- [ laughter ] we've done all sorts of elephant's toothpaste. let's stand right here. we've never actually done it inside. >> that's true. >> mark: as an engineer you build models. this happens to be randomly a diorama of jimmy's office. >> looks just like it. [ laughter ] >> mark: man of science. what would happen if we did it in an office? jimmy's. randomly, jimmy's office. >> i would think, if you were going to hypothetically do this. >> mark: if you were going to. >> probably put some hydrogen peroxide there, a mechanism with -- >> mark: what would that look like? >> that would probably look -- that's kind of cool. yeah, that would be neat. >> mark: that would be neat. >> yeah, that would be neat.

>> mark: huh. [ laughter ] you have any more hydrogen peroxide? >> i've got a whole truck of this stuff out there. >> mark: great. when we come back, bob and i are going to take things up a notch. [ cheers and applause ] so do not go anywhere! ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪ ♪

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so do not go anywhere! >> mark: welcome back. i'm mark rober here with science bob. we have one more big experiment planned. the elephant toothpaste demonstration we did before the break, that was using just 50 milliliters of hydrogen peroxide. but this is tv. on tv, you go bigger. so we figured, why not see what happens if we do the same thing with a lot more milliliters of hydrogen peroxide? how many milliliters will that be, bob? >> well, that would be 113,562 milliliters. >> mark: okay, okay. that's going to create thousands of times more foam.

so we needed to find a space slightly bigger than just a tabletop model. we're here in the perfect-sized room to completely fill with elephant toothpaste. where are we, guillermo? >> guillermo: jimmy's office. >> mark: you're sure he's okay with this? >> guillermo: he loves pranks. >> mark: that's all i need to hear. let's get to work. watch your head. that's about 25, bob. >> what do you think, one barrel or two? >> mark: two, i think. up to the ceiling, right? jimmy has quite a few pictures of himself, i'm noticing. >> you know what i don't like? there's not a single picture of me in this office. >> mark: are you sure? >> guillermo: yeah. [ bleep ] you, jimmy. >> mark: what is this, a clarinet? >> guillermo: yeah. >> mark: guillermo, this is how it's going to work. you're going to have this rope. we built this contraption such that when you pull that rope, not yet, this platform will tip down, the catalyst will go into the hydrogen peroxide, then we get elephant toothpaste. just like that. >> guillermo: just like that? >> mark: just like that.

if this were a real demonstration, you'd be possibly dead. you'd need to get out of here, it would be bad news. >> guillermo: oh, [ bleep ]. >> you've got to run. [ laughter ] >> i think he'll live. >> mark: i hope. ♪ goggle up for safety. all right, gentlemen. i think our work here is done. [ cheers and applause ] okay, so right now at this very moment, jimmy's office is rigged to explode with a massive amount of elephant toothpaste. and guillermo is upstairs in a hazmat suit in jimmy's office, standing by to trigger it. you ready, guillermo? >> guillermo: let's do this! [ laughter ] >> mark: okay. before we go, there's someone i wanted to call. can we get him on the screen here?

everybody, it's jimmy kimmel! >> jimmy: what is this? [ cheers and applause ] >> mark: jimmy, how is your vacation going so far, buddy? >> jimmy: it's going really good. look at this. i'm wearing sandals. [ laughter ] >> mark: hey. all right. well, we're about to do a science demo. we know how much you love science. but first, i've got to ask you if you recognize this room. >> jimmy: yes, i do. that is my office. >> guillermo: hi, jimmy! >> jimmy: hi, guillermo. >> mark: that's right. how do you feel about the rapid expansion of a hot gas due to a catalyst in a subvolumetric receptacle? >> jimmy: you know i've always been very pro that. [ laughter ] >> mark: thank goodness. >> that's good. >> mark: that is a huge relief. in that case, all right, audience, let's count them down. three, two, one -- hit it, guillermo!

♪ >> jimmy: what in the world? that's my office! [ cheers and applause ] >> mark: so -- yeah. it was guillermo's idea, jimmy! it was guillermo's idea! >> jimmy: that doesn't sound like one of guillermo's ideas to me. [ laughter and applause ] you think this fascination with elephant paste explosions indicates some kind of a deep-seated sexual frustration? perhaps between the two of you? i don't know. >> mark: that's what happens when you leave the nerds in charge, jimmy. well, thank you for letting me host --

>> jimmy: wait, it's not going to disappear now or something? >> guillermo: no. >> two or three months. >> mark: that's not our problem, jimmy. we're out of here. >> [ bleep ]. >> jimmy: all right. well, my attorneys will be in touch. [ laughter ] don't you laugh, guillermo. you'll still be there when i get back. [ laughter ] >> mark: it was his idea right here! the white guy right here, jimmy! [ laughter and applause ] >> mark: this white guy, this white guy. thank you for letting me host your show for what i'm sure will be the last time. >> jimmy: that's right, yeah. >> mark: we'll be right back with music from demi lovato! [ cheers and applause ] >> lou: the "jimmy kimmel live" concert series is presented by mercedes-benz. the best or nothing.

♪ ♪ the thing that's different about a vrbo vacation home. you always have the whole place to yourself. no stranger at the dinner table making things awkward. or in another room taking up space. it's just you and your people. because why would you ever share your vacation home with someone you wouldn't share your vacation with. ♪ ♪ wanna help kids get their homework done? withwell, an internetdn't connection's a good start. but kids also need computers. and sometimes the hardest thing about homework is finding a place to do it. so why not hook community centers up with wifi? for kids like us, and all the amazing things we're gonna learn. through project up, comcast is committing $1 billion dollars so millions more students can continue to get the tools they need to build a future of unlimited possibilities.

large out-of-state corporations have set their sights on california. they've written prop 27, to allow online sports betting. they tell us it will fund programs for the homeless. but read prop 27's fine print. 90% of profits go to out-of-state corporations, leaving almost nothing for the homeless. no real jobs are created here. but the promise between our state and our sovereign tribes would be broken forever. these out-of-state corporations don't care about california. but we do. stand with us. >> lou: the "jimmy kimmel live" concert series is presented by mercedes eq. all electric, all mercedes. >> mark: that's all the time we have. i want to thank science bob pflugfelder, jimmy kimmel for letting me destroy his stuff, apology to mr. beast, we ran out of time. "nightline" is next. first, "holy f" is out on august 19th.

here with their brand-new single "substance," demi lovato! [ cheers and applause ] ♪ ♪ ♪ is anybody happy with life in the back seat ♪ ♪ trying to master the art of detaching ♪ ♪ is anybody driving is anyone asking is anyone grasping that nothing lasts ♪ ♪ whoa i know we're all exhausted ♪ ♪ whoa am i in my head or have we all lost it ♪ ♪ so i ask myself am i the only one looking for substance ♪ ♪ got high it only left me lonely and loveless ♪ ♪ don't wanna end up in a casket head full of maggots ♪ ♪ body full of jack get an abundance ♪ ♪ am i the only one looking for substance ♪

♪ i don't remember last week got my head scratching ♪ ♪ everyone's acting like nothing is lacking ♪ ♪ think we might be crashing everyone's laughing ♪ ♪ time is just passing yet nothing lasts ♪ ♪ whoa i know we're all exhausted ♪ ♪ whoa am i in my head or have we all lost it ♪ ♪ so i ask myself am i the only one looking for substance ♪ ♪ got high it only left me lonely and loveless ♪ ♪ don't wanna end up in a casket head full of maggots ♪ ♪ body full of jack get an abundance ♪ ♪ am i the only one looking for substance ♪

♪ ♪ am i talking to myself is anyone out there screaming at the walls ♪ ♪ i can't relate at all relate at all ♪ ♪ the theatrics what happened to classic ♪ ♪ give me the real give me the magic ♪ ♪ so i ask myself am i the only one looking for substance ♪ ♪ got high it only left me lonely and loveless ♪ ♪ don't wanna end up in a casket head full of maggots ♪ ♪ body full of jack i get an abundance ♪ ♪ my the only one looking for substance ♪ ♪ yeah yeah yeah yeah yeah yeah ♪ [ cheers and applause ]

tonight -- as the battle over abortion rages across the country, the women caught in the middle. >> it's not that i didn't want kids, i didn't want kids at 18. >> with dwindling options, some women of turning to crisis pregnancy center. >> this is our ultrasound room. if she'd come here and seen this and chose abortion, we'd like her to see. >> it saved my life, really did. >> they are not replacements for clinics. if it was up to me, they'd be shut down and defunded entirely. >> women navigating a