Bell Hoppy is a 1954 Warner Bros. Merrie Melodies cartoon short directed by Robert McKimson.
Sylvester comes into the picture when – wanting to join a fraternal organization called "the Loyal Order of Alley Cats Mouse and Chowder Club" – he is offered the opportunity for membership by the leader of the club by successfully placing the bell around the mouse's neck.
Sylvester is, naturally, excited about finally one-upping his long-time nemesis and calls the cats into position.
But by the time the cats are ready to pounce on the baby kangaroo-mistaken-for-a-giant-mouse, Hippety is back in the city zoo truck and very happy with his new toy.
Taking the opportunity, Sylvester now gets to serve as the Brotherhood's Grand High Exalted Poobah (since he is now the only active member because the others are all bandaged up) only to be "blackballed" again...this time after declaring himself leader and pounding the gavel on the table too hard, causing the black 8 billiard ball on the table to bounce up and hit him on the top of his head.