He has also eaten his own face.
Gary Busey's teeth are larger than his head. How is this possible? At some point in the past, he must have started to eat himself from the inside out. He has now eaten all of the muscle and tissue inside his own head and all that's left is skin and a giant set of teeth on the outside of his body. Somebody needs to stop this man before he eats us all.
(See the comments below for the real reason why Gary Busey looks so weird...)
|Gary Busey ...|
|... has already eaten himself ...|
|... and will eat us all ...|
|... if these riot police* don't stop him first.|
*they're actually firemen, but don't let that ruin a good story.