A Red I is an relative of a Mr. I that is only seen in Castle Bleck specifically Castle Bleck Entry and Castle Bleck Foyer. Red Is, much like Mr. Is, attack by firing a laser beam from its pupil. They cannot be defeated by normal means. The only way to defeat them is to use Mario's Flip to flip into 3-D and run around them to make them dizzy which will defeat the Red I.