17. Dizaster vs. DNA
In 2009, while battling Toronto rapper Organik in the Bay, LA's Dizaster said, among other things, "Canadians are faggots." (Note: Diz's first volley was an extended takedown of the country, saying that our neighbors to the north are effeminate and/or weak for many reasons, one of them somehow because they have universal health care.) Two years later, Dizaster met New York's DNA in Toronto; Drake and Organik co-hosted the event.
Lo and behold, in the final moments of the 45 minute back-and-forth, DNA dared Dizaster to say what he had said to Organik those years before. Dizaster took the bait at first, and quietly repeated, "Canadians are faggots," muttering the line through his teeth. And then the boos rained down. DNA chided him for saying that in front of Drake, in front of Organik, and for saying it originally in Oakland, where there would be no repercussions. So, DNA dared him to say it again. He didn't. That last five minutes might be the most thrilling dissection of a rapper in battle, ever.