the bear's tricks are so unbelievable that even alex's sister, yuki, thinks it's a fake. >> there's aazy stuff in japan, so i thought maybe it was a show or something. then he's like, no, it's real. >> alex uploads the video in september 2009. >> i start getting thousands of views. started getting really excited. and then just week after week it kept blowing up. >> before long, the video entitled "kung fu bear" receives more than 3.5 million hits on youtube. the video's so popular, it spawns numerous parodies. >> good morning, ninja bear. time to complete your ninja training. >> it's almost like the entire internet was riffing on this video for a little bit. >> i've seen like "mortal combat" sounds, that sort of thing. >> the light saber version where the bear's carrying a light saber instead of a stick. that one's funny. >> people want to recontextualize anything that's popular. it's a way to participate in the viral revolution. >> but with growing popularity comes growing skepticism. many viewers think alex's video is a fake. >> the part where he flips the stick in the air and catch

yuki kamio, the master.point between the karate and the sushi? but this moment is so much good for when i make my sushi because of the stance. the other different type of karate, the stance is a little bit more upper. so this karate is a little bit more deep. this. so standing in front of the cutting board, little bit of the deep stance and movement. deep stance and body movement and watch from left to the right. move this, move this. watch this and watch this. this is the key. so this karate is my sushi moves. ♪ >> now, in an official tournament, two-minute rounds. >> two-minute round. and the result you're looking for is points? >> points, or knockdown. but two minutes fight. one minutes fight. that's most hardest. >> it's underground. you can just work on their legs for five, seven minutes to slow them down. then you go in? >> yes. and no compromise. just do it. whatever happen, no excuse. see the result good or not. if it's bad, try again. don't give up. >> right. >> this is my sushi. >> perfect. could s