Big Mr. I

Big Mr. I is a boss found in Big Boo's Haunt, and is a larger version of the Mr. I enemy. It is found in a room of Big Boo's Haunt's attic, requiring the Vanish Cap to access. They have the exact same behavior as the regular Mr. I, shooting orbs at the player upon focusing on them, and being defeated when ran around enough. When defeated, it drops the "Eye To Eye In The Secret Room" mission's star.

Bigger Mr. I
In some personalized copies of Super Mario 64, Big Mr. I is seemingly bigger, and harder to get around in order to defeat it.