What kind of utter douchebag fights by
biting the other guy's ear? Who does he think he is, Mike Tyson? Nobody does this! That an a$$hole!
I want the doctor to take your picture so I can look at you from inside as well.
it's quite funny that he chases after him to continue the fight (after being punched outside the school), but quickly realises that he's completely out-muscled by Skip, so has to run away instead. The ear-bite you refer to is a desperate move stop the attack, and also to buy himself some time to get away. Same with throwing the rock and the fire extinguisher at him.
It accomplished what he wanted though, in making Skip finally get it out of his system. Not just for the sake of their friendship, for Skip's own sanity too