Cubuladon

Cubuladon is a mini-boss that appears in Enter the Gungeon, in the Gungeon Proper, Black Powder Mine, Hollow, or the Resourceful Rat's Lair, they spawn in a room roughly the same size as a boss room. To unlock the Mini-boss, you must pick up a bounty, from The Bullet Prince. The Cubuladon bounty is the first bounty in the Enter the Gungeon game.