Nightmare imp



The nightmare imp is a translucent blue and purple imp which is the first new monster encountered in Doom 64. It moves twice as fast as the standard imp, and it hurls purple fireballs which also move twice as fast as those of the standard imp. These properties make it similar to the ordinary imps in Doom's Nightmare! skill level, serving as the source of the creature's name. It is described as follows: "An Imp is bad enough, but picture a faster, more aggressive one. Now the bad news... he's harder to see, too."

- Doom 64 instruction manual

Origin
A press release beta of the Sony PlayStation version of Doom included nightmare imps which, like the nightmare spectre in the same game, were subtractively blended against the background and had double the health of normal imps. A screenshot of the monster appears in a pre-release review in UK game magazine Maximum with the following description:

All such nightmare imps were removed from the game before its final release for reasons unknown. The technical capacity for this enemy to exist is still part of the game engine, as any thing which can be placed on a map can be given the "nightmare" flag, and will become subtractively blended and double its spawn health.