Melissa McCarthy will host 'SNL' for the third time this week (Feb. 1), with rockers Imagine Dragons serving as the musical guest. In the promos, the hilarious actress beats the crap out of cast member Kenan Thompson.

What did Thompson do to run afoul of Miss McCarthy?

When he celebrates the third time being the charm for her as host, she assumes he meant her two previous stints sucked, so she punches him in the face and karate chops his back, forcing him to say that she was great before. BRILLIANT!

They make up quickly and improvise a new song called 'Imagine Dragons.' They are quite a musical duo. They also get a mean case of cramps during their celebration dance.

McCarthy also sets the Olympic torch on fire…sort of.

Do not mess with Melissa McCarthy. And be sure to watch her this Saturday night, live from New York.