Big Mr. I.

Big Mr. I. is a large Mr. I that appears as a boss in Super Mario 64. He can be found in Big Boo's Haunt. However, to reach him, Mario has to go up to the attic, which leads to the balcony. Mario must then go to the balcony on the second floor, grab the Vanish Cap, and run into the Boo painting in the attic. He is then in a room with Big Mr. I. and his Boo ally, and he must get his attention. Once he does, Mario must run around Big Mr. I. once either clockwise or counterclockwise, causing Big Mr. I. to get dizzy and spin around uncontrollably until he disappears and turns into a Power Star. He appears again in the game's Nintendo DS remake, Super Mario 64 DS, with the same role and abilities. In this version, Luigi is required to defeat Big Mr. I. since Luigi is the only player character who can turn invisible. Big Mr. I., along with the Big Bully, Big Boo, and Chill Bully, does not speak to the player character or have the boss theme play during his fight.

In Mario Golf, Big Mr. I. occasionally appears on the score card.