Basically the Brain behind the Brain Dead, He controls the Blood Puppets from behind the wall. When the battle begins, a Blood Puppet supposedly warns the others (and Balloon Head) of Rick's presense, starting the fight. Ballon Head then attempts to attack Rick with a Chainsaw and Hedgeclippers while Blood Puppets fall and rise from the ceiling before using just the puppets themselves. After enough are defeated, he kills four more (out of possible frustration), bursting through the wall and leaving himself helpless to attack. Upon defeat, he explodes in a sea of blood.
Balloon Head himself can't attack Rick, so he uses the Blood Puppets as well as a hedge clipper and chainsaw to attack you, instead. After Rick has defeated the chainsaw (or take too long to fight it), Blood Puppets start attacking you. After enough are killed, a strange event involving the Blood Puppets falling down and behaving as if they were being cut up by the chainsaw, before Balloon Head smashed thorugh the wall, leaving him vunerable to Rick's attacks.