8. Chael Sonnen

Sport: MMA
Career: 1997-Present
Cockiest Quote: “I want an easy fight. Anderson Silva, Wanderlei Silva. Either of the Silvas. Bigfoot Silva. They all suck. Gimme a Silva.”

Prior to his UFC 117 matchup with Anderson Silva, Sonnen went on a veritable trash-talking rampage, dissing Silva's martial arts bonafides (“A black belt from the Nogueira brothers is like saying I got a free toy in my happy meal”) and threatening Silva with unsportsmanlike (and unsanitary) violence (“I'll smile to his face and if he turns his back I'm gonna stick a knife in him and walk away without even cleaning up the mess”). He also (allegedly) made a series of funny ("you are going to be on your back more than a pornstar with a mortgage") and racist ("pray to whatever Demon effigy you prance and dance in front of with your piglet tribe of savages that I decide not to CRUCIFY you") tweets from an account he later claimed was a fake. Whatever. But after talking the talk, could he walk the walk? Turns out yes, to a point. He bested Silva on all the judges cards through four rounds, only to tap out with 3:10 left in the fight. He was subsequently suspended for having an elevated testosterone level, which might explain the extraordinary performance-and the extraordinary trash talk.