Its appearance is that of a simple face with unevenly placed, square shaped eyes and a laughing red mouth. The eyes consist of two purple squares surrounding a small red square.
It appears in all of the closets in The Guillotine World except for one, which is the one Madotsuki is able to use to escape to Number World, exiting through one of the closets in the Bed Room. If Madotsuki opens a closet inhabited by a Closet Creature, it will cackle and the closet immediately shuts again. Thus the Closet Creature seemingly mocks Madotsuki for choosing the wrong closet. The number of Closet Creatures in The Guillotine World depends on Madotsuki having entered Big Guillotine World or not.
- It vaguely resembles the laughing face on Number World's wallpaper.