Judas the Mule, was a vicious, ill-tempered brute who belonged to Doc Tanner. They had a love/hate relationship - Judas would often try to bite or kick Doc, but he had an uncommon affection for his master and saved his life on several occasions. When a pair of travelers brought a leaking nuclear warhead to Jak's second farm, irreversibly contaminating the area, the companions fled to a dam several miles away; they decided to use the mat-trans to jump to a new place, so Doc was finally forced to set Judas free. (Genesis Echo)
Biting, and kicking.