The Maradan Prison is where pets are confined when they have committed a crime. Your pet can go to prison if caught using illegal items. Any illegal jobs can also send your pet to prison. But not paying your electricity bills at the powerstation will definitely send one of your pets to prison. If your pet is in prison below, you will have two options:

You can pay the 2,500MP fine to free your pet but it will change to a Prison coloured pet.

You can bribe the prison guard, Corporal Knifejaw, with 15,000MP and it will leave prison unchanged.