BlackJack O-Hare first appeared in Incredible Hulk #271. Yes. I know. He's a bunny. In fact he's the leader of the notorious Black Bunny Brigade.
O'Hare has many of the same attributes of an average rabbit except for his intellect which enables him to speak, among other things such as use advanced weaponry and carry out complex tasks with extreme precision. He, unlike other rabbits, can walk upright.
Blackjack was the leader of the Black Bunny Brigade. The Brigade was hired by the devious Judson Jakes to steal the most prized relic of Halfworld, the Gideon Bible. He was successful in stealing the Bible and he kidnapped Rocket Raccoon's girlfriend, Lylla the Otter on the way. The Hulk helped Rocket and Rocket's best friend Wal Rus defeat Jakes and his posse of killer clowns to recover both Lylla and the Bible.