Koopatraz State Prison

Koopatraz State Prison, usually just referred to simply as Koopatraz, was a maximum security penitentiary situated on a small island in Trouter Bay. Until its demise, Koopatraz State Prison was owned and operated by Warden Koopa, and used as a dungeon to house many of his own prisoners. Bailiff Mouser also served as Koopatraz's second-in-command. Surrounded by large walls and a water tower, the prison contained cell blocks for both male and female prisoners, in addition to solitary cells. Other known rooms included a mess hall, a laundry room and sleeping quarters for its staff.

Although many prisoners used to live in Koopatraz State Prison, most of them had passed away by the time it sank beneath Trouter Bay. Known punishments forced upon the prisoners included meals consisting of bread, water and Koopa Surprise, breaking rocks and laundry duty.

History
Mario, Luigi, Princess Toadstool and Toad were captured by King Koopa, and eventually put on trial before him, while he posed as the judge. Regardless of their actions, Judge Koopa made up a bunch of lies, and sentenced them all to serve five-hundred years at Koopatraz State Prison. Upon arriving, they were greeted by Warden Koopa, who became their cruel warden because he had so much fun being their crooked judge. Mario, Luigi and Toad were assigned to share a cell with Gramps, Koopatraz's only other living prisoner, while Princess Toadstool was placed in her own cell.

After Toad reunited with Gramps, Mario came up with an escape plan that involved digging under the prison to reach the other side of the front gate, where they could escape on a boat. In order to steal the forks necessary for the job, Mario started a food fight in the mess hall, which resulted in Warden Koopa revoking their future meals. Using forks they stole, the male prisoners dug a tunnel, but accidentally surfaced in Warden Koopa's bedroom, greatly angering him. As a result, he extended their sentence and assigned them to hard labor.

Mario stole a block of soap during laundry duty, and whittled a phony Bob-omb from it, which he used to scare a Goomba guard, whose keys he stole. Mario used the keys to rescue the rest of the prisoners, and they escaped from Warden Koopa by jumping down a sewer drain, which led them to a cavern with a large drain stopper. The group pulled out the drain stopper, and surfaced next to the island, where they escaped on a boat, while the island began to flood. Warden Koopa attempted to thwart their escape with a Bob-omb, but it failed, and soon the entire island of Kooaptraz State Prison sank beneath Trouter Bay.

Trivia

 * Koopatraz was based on Alcatraz, a famous jail off the coast of San Francisco, California.