Private Koopa is a character that appears in Super Paper Mario.
Private Koopa is one of many members of the Koopa Troop that has been warped to Castle Bleck during the events of the game. He met up with the Hammer Bro Captain and walked around until they ran into Princess Peach. After some talking, the Hammer Bro Captain told Private Koopa to follow Princess Peach and try to find a way out. Unfortunately, they were soon discovered by Nastasia and Private Koopa was brainwashed into working for Count Bleck.