The worst foul in modern MMA history occurred in Portland, Oregon, on Aug. 29, 2009.
Chris Tuchscherer's heavyweight bout against Gabriel Gonzaga that night at UFC 102 had just begun when Gonzaga threw his 6'2", 264-pound frame into a kick aimed at the inside of Tuchscherer's thigh. Unfortunately, Gonzaga missed his mark, and the full force of his kick landed squarely on the UFC newcomer's groin.
Tuchscherer's mind told him to fight on, but his body failed him. He collapsed in a heap and spent the next few minutes writhing and dry heaving on the Octagon floor, surrounded by cageside officials.