Imp

The Imp is a small humanoid demon, the most common monster encountered in id Software's IWADs. He is brown in color, with red eyes, a few white spikes on his body, and noticeable white claws on his hands and feet.

The Doom instruction manual says:
 * You thought an imp was a cute little dude in a red suit with a pitchfork. Where did these brown bastards come from? They heave balls o' fire down your throat and take several bullets to die. It's time to find a weapon better than that pistol if you're going to face more than one of these S.O.B.s.

The Imp first appears in E1M1: Hangar (irrespective of skill level).

Combat characteristics
An Imp attacks by ejecting a single fireball, which does not inflict blast damage. At melee range, he can also employ a somewhat more powerful clawing attack.

Tactical analysis
The Imp moves slowly, as do his fireballs. The player should practice until evading both sorts of objects becomes completely straightforward (except perhaps under highly unusual circumstances, such as a teleportation trap in close quarters).

An Imp can be killed by one shotgun shell (usually) or six bullets (often). As the above quotation implies, facing down multiple Imps with a pistol takes concentration, but it can be done, given sufficient maneuvering room and adequate footwork on the player's part. (In fact, the Imp's relatively high pain chance sometimes makes it difficult for him to retaliate at point-blank range.)

Although his ranged attack and hit point total give him some purchase against zombies, the Imp can easily find himself overmatched in monster-monster battles. A single Imp fighting a sergeant has cause for optimism, but a Demon or Spectre can almost always outslug the first two or three Imps he engages in melee, and a direct hit by any larger monster is normally too much for an Imp.

Imp fireballs move 50% faster than normal when the Nightmare! skill level or the -fast command line parameter is used.

Appearance statistics
The IWADs contain the following numbers of Imps: