The Ghost Hunter Haunter is the main antagonist of the 2006 Scooby-Doo! video game, Scooby-Doo! Who's Watching thumb|273px|link=File:Ghost_Hunter_Haunter_(GSI).pngWho?.
Role in the Game
When Scooby-Doo and his friends guest star on the show, Ghost Scene Investagations, The Ghost Hunter Haunter sends some past Scooby-Doo! Monsters like the Ghost of Redbeard, The Ghost Clown, The Space Kook, The Phantom Shadow and the Ghost of Elias Kingston after them.
He is first seen after Scooby and the gang defeated Elias Kingston in the game's first episode. He is later seen again after Scooby and the gang defeat the Clown in the second episode. He was also watching the gang when they caught the Space Kook in the third episode. He isn't seen once during the fourth episode. Finally Scooby, the gang and the Ghost Scene Investigators teamed up so they could take the Ghost Hunter Haunter down in the final episode. After The Ghost Hunter Haunter defeated, He is unmasked as the show's producer Mace Middlemost who wanted to drive up the show's ratings.