A Tobin scan of this ghost reveals it is a Class V Full Roaming Telekinetic Vapor.
It appears, with and without horns, in the Museum of Natural History levels of Multiplayer Mode.
Ghoul has heavy trap resistance. One of his attacks involves vomiting brown ectoplasm in your direction (much like the Sloth Ghost), so it might be a good idea to keep moving when encountering it.
- Ghoul was also available as a controllable character in the game's pre-order bonus pack.