There are tough guys and then there are trained martial artists.

Here is a video from BJJ black belt Robson Moura showing a big and tough-looking that went into his school and challenged anyone to a fight, for $20.

Moura took the offer and according to the video description, Moura said that if he beat the large man in five minutes, he would have to sign up for his classes.

See the BJJ world champion Robson Moura go to work on his oversized opponent in the video above.