Red: Because of its ability to slip through block walls, it is said to be from an other dimension.Yellow: By licking, it saps the victim's life. It causes shaking that won't stop until the victim's demise.Gold: In total darkness, where nothing is visible, HAUNTER lurks, silently stalking its next victim.
Prof. Lotus' Notes: Haunter is possibly a portmanteau of Hunter (due to it's stalker nature), haunt and Spectre (Haunter's original name in the Pokemon Red / Blue beta). Haunter is one of 4 of the lightest Pokemon weighing in at 0.1KG.