VIDEO: Velasquez, Werdum engage in intense staredown; Werdum busts out troll face

UFC heavyweight champion Cain Velasquez and interim heavyweight champion Fabricio Werdum engaged in a staredown Thursday in anticipation of Saturday's title bout at UFC 188 in Mexico City.

After what felt like an eternity of intense indigestion-face, Werdum finally broke down and busted out his patented troll face, and followed it up with a gigantic goofy grin.

Velasquez ... well, he was not in the smiling mood.