i'd like you to please welcome our in-house hip-hop historian, gary greenburg, everybody. [ cheers and applause ] hi, gary. >> hi. so i thought i would explain everything in the form of a rap. band, give me a beat! ♪ ♪ ♪ ♪ >> jimmy: oh, no, no, no beat. ♪ my name is gary hope you like my flow been rhyming since 1984 ♪ >> jimmy: no, the band can't give you a beat. >> you don't want the rap? >> jimmy: no, i don't want the rap. i think it might be bad for both of us. and please take the hat off. [ laughter ] >> okay. i guess i'll do the powerpoint presentation. >> jimmy: yes, do a powerpoint presentation, it will be better. all right, here we go. >> "kendrick vs. drake: where's the beef?" [ laughter ] 2012. drake and kendrick are besties. drake even took kendrick on tour with him. but in 2013, everything changed. kendrick featured on "control," a diss track where he called out many of the biggest names in rap, including drake. diss means diss as in "disrespectful" and track -- >>. >> jimmy: we know. we know that. >> kendrick rapped -- "one at a time, i line 'em up and bomb on they mom." >