Ghosane

Ghosane is a ghost/steel Pokemon that is based heavily on Marley's Ghost.

How To Get
Ghosane cannot be captured in tall grass. Instead, at the area Melvin's Mansion, they stalk you in certain rooms. This is only if you happen to have a key collected, though, otherwise they will silently walk away.

Bohooed also evolves into it at level 40.

Trivia

 * When the word Ghosane is broken apart, it means Ghost and Sane, or Insane, which may suggest this Pokemon tries to maintain it's sanity.