One of the greatest examples of the absurd lengths fighters will go to while cutting weight is that light heavyweight contender Anthony "Rumble" Johnson spent a good portion of his career at welterweight.
This made for a number of lopsided matches where Johnson mauled much, much smaller opponents. The greatest example of this? His UFC on Versus 6 bout with future lightweight Charlie Brenneman. Watch the full fight here:
The future light heavyweight utterly thrashed the soon-to-be 155-pounder, effortlessly muscling his way around his grappling attack and wrenching his way through transitions. The finish comes in the first round, as Johnson drills him with a pair of headkicks that send him (and his afro) whipping to the mat.
Despite the victory (and successfully making weight), that wound up as Johnson's last at 170 pounds. He was released from the UFC after a loss in his middleweight debut. Then, while competing on the indie circuit, he moved up to 205 pounds, and even took a heavyweight fight against former UFC champ Andrei Arlovski.
He'll have the chance to take the UFC light heavyweight title from Daniel Cormier on Saturday night. He won't have a size advantage, but his power alone makes him a serious threat to the champ.