Dupe appears as a disembodied white face with a large, toothy smile with bloody teeth and a pair of bloodshot eyes, with a shadowy female body, and a cartoonish demon tail. Dupe has a chance to spawn fake doors in rooms with multiple possible doorways. There can be multiple Dupe doors, each marked with an incorrect number. If the player attempts to enter a Dupe door, the player will be attacked by her.