The “Haunted Mansion Fan” is a young human boy.
In 2011, this brown-haired boy who (going by his T-shirt) appears to be a fan of the Haunted Mansion, decided to sneak into the house himself, on foot, outside of regular tour hours. As he entered the Stretching Room, he realized that he had disturbed one of Madame Leota's incantations, and the ghostly witch sent him on a tumbling journey of terror through the house in retaliation, with the Ghost Host's mocking, but occasionally helpful, voice as his guide. Dodging the pranks of Phineas and the attacks of the Black Widow Bride, he finally made it out of the Mansion, scared out of his wits, thanks to the directions given by the Hitchhiking Ghosts.
Behind the scenes
This boy is a possible player character in the non-canonical video game Kinect Disneyland Adventures, and was created for this purpose. He debuted a week before the game's release in the promotional webcast Haunted Mansion Cutscenes.