"You want my knowledge? I don't mind giving it to you, but can you use it?"
This subspecies of Metal Ghost is said to have changed after having amassed extensive records on the element of water. One must be patient in keeping company with them as they often complain by saying things like "I like cool places but I hate the cold," and "I don't like my food too hot or too cold." The element of water is much stronger in them than in normal Metal Ghosts, and it's said that when fused to other water types they provide loads more experience as well.
Water Ghosts are best used as an ingredient for fusion, providing a base of 1,506 XP. When fused with Water element units, it grants 2,259 XP, not including Great Success (x1.5) or Super Success (x2). The Water Ghosts only sell for 1,000 Zel each.