Count Geoffrey was not intending for him to be a rabbit, but used this to his advantage and had his Evil Spy put in a suggestion for the Code of Chivalry to forbid dragon knights from hurting rabbits, which would ensure Sir Hare's victory.
Sir Hare did not seem evil so Geoffrey stopped feeding him in order to make him aggressive, and promised to feed him carrots if he beat Sir Loungelot. Sir Hare gave Sir Loungelot a beating before Flicker sprayed Geoffrey and his Evil Knights with orange paint. Thinking they were carrots, Sir Hare chased them into the distance.
Sir Hare hasn't been seen or mentioned since.