Ghost as they appear in the Wonderland game series.
The Ghosts are enemies that are from Return to Wonderland and Wonderland Secret Worlds. Their movement is usually faster than Coilys and slower than the Kabooms. Ghosts don't cross water, lava, or empty space but they can pass through gates, enemies, and all movable objects exept for Plasma Boxes, they will block them and they also expload if they get near a Powder Keg. They can't press buttons either. They won't die if a fireball hits them because fireballs can go through ghosts and the continues its normal path.
In Wonderland Adventures: Planet of the Z-Bots, Ghosts reappear when The Creepy Keep is revisited, now they have a messed up pink texture and they slowly chase the player. They disappear if the player is away from them and reappear when the player comes close again.