Duppy

Duppies are ghostly enemies found in Tunnels from Nowhere. They are cyan, spherical beings with red-lined eyes and white pupils. Small particles rise off their body in a way reminiscent of fire. They slowly drift toward the player on sight, and fire a powerful shriek projectile before blurring themselves and flying into a new position. They are only tangible to attacks when they are fully visible.

The word "duppy" is simply a synonym for "ghost", indicating that duppies are distinct from the broader scope of ghosts but undeniably related.