Quote Originally Posted by splinter
I could be wrong, but I seem to remember seeing a Vale Tudo fight with Chuck Liddell where he was trying to stomp on his downed opponent's nutz.

The opponent was on the grownd defending with his legs. Liddell was basically alternating with leg kicks and attempted groin stomps. It made me cringe more than just about anything else I've seen in MMA.
Liddel vs Pele, in Chuck's second ever pro mma fight. IVC 6.