For information about the Spectre enemy from Strife, see Spectre (Strife).

A spectre about to bite the player in Doom II MAP08: Tricks and Traps.

Spectres are the partially invisible counterparts of demons. Except for their fuzzy, blurred appearance, they are exactly the same in behavior and attributes, and thus may be thought of as demons who have a permanent partial invisibility power. They usually hide in darkened areas, waiting to startle players. Spectres do not have frames of their own, as the Doom engine uses the same information used for demons to account for them, which means the monsters share sprites.

Spectres appear as "shimmering" beings, like a lens which distorts and reflects the area seen through their translucent bodies, making them hard to spot in darker areas or against certain textures, such as grey speckled walls. However, in bright areas, they are noticeably visible and "spotty".

In the Doom II manual, their description is: Great. Just what you needed. An invisible (nearly) monster.

Variations

The initial opaque appearance of a spectre in Doom 64.

In many OpenGL source ports, as well as in Doom 64 and the Sony PlayStation version of Doom, spectres do not "shimmer", but are instead rendered using translucency. This is because the partial invisibility effect is very difficult to reproduce using such a renderer. EDGE, however, emulates the effect using a shader, and GZDoom allows users to select one of several "simulated" effect presets to suit their tastes.

In Doom 64 specifically, inactive spectres are initially rendered as opaque demons with a green tint, becoming translucent upon detecting the player. Upon death, they revert to an opaque state again. Spectres also appear in the Doom 64 Cast of Characters sequence at the end of the game, unlike the spectre in the Doom II cast sequence.

The PlayStation version, aside from featuring ordinary spectres at both 25% and 100% additive translucency levels, introduced a stronger version of the spectre called the nightmare spectre.

Notes

• There are some tricks that can help make spectres more visible: their shimmering outline is much easier to see with the inverted colors of an invulnerability sphere, for example, and they feature a fully visible blood-splatter effect when hit.
• The spectre does not appear in the Doom II cast sequence at the end of the game.
• If a spectre's corpse is crushed, the pool of gibs left behind continues to display the partial invisibility effect. In most hardware accelerated ports, the gibs will be translucent.

Data

Attributes ID # 58 (decimal), 3A (hex) Hit points 150 Speed 10 map units per frame (175.0 map units per second) Width 60 Height 56 Reaction time 8 Pain chance 180 (70.70%) Pain time 4 tics Mass 400 Bits 4194310 Bits list 1: Obstacle 2: Shootable 22: Affects Kill %

Sprites & sounds Sprite name SARG Alert sound DSSGTSIT Action sound DSDMACT Pain sound DSDMPAIN Death sound DSSGTDTH

Melee attack Damage 4-40 Sound DSSGTATK

Damage done by a spectre's bite

Bites needed to kill1	Mean	Standard deviation	Min	Max
Player (100% health, no armor)	5.16	1.20	3	9
Player (100% health, security armor)	7.32	1.33	5	11
Player (200% health, combat armor)	18.86	1.60	15	22
Barrel	1.50	0.66	1	5
Trooper	1.50	0.66	1	5
Sergeant	1.97	0.77	1	5
Wolfenstein SS	2.98	0.95	2	7
Imp	3.29	0.99	2	7
Chaingunner	3.84	0.99	2	8
Lost soul	5.16	1.20	3	9
Commander Keen	5.16	1.20	3	9
Demon	7.48	1.31	5	11
Spectre	7.48	1.31	5	11
Boss brain2	12.15	1.59	8	17
Revenant	14.31	1.57	11	18
Cacodemon	18.86	1.60	15	22
Pain elemental	18.86	1.60	15	22
Hell knight	23.52	1.50	19	27
Arachnotron	23.52	1.50	19	27
Mancubus	28.15	1.35	24	32
Arch-vile	32.84	1.30	30	36
Baron of Hell	46.72	1.79	42	51
Spiderdemon	139.43	2.32	134	144
Cyberdemon	185.64	2.97	180	192

1. This table assumes that all calls to P_Random for damage, pain chance, and blood splats are consecutive. In real play, this is never the case: counterattacks and AI pathfinding must be handled, and of course the map may contain additional moving monsters and other randomized phenomena (such as flickering lights). Any resulting errors are probably toward the single-shot average, as they introduce noise into the correlation between the indices of "consecutive" calls.
2. Assumes that direct hits are possible, which does not occur in any stock map.

Appearance statistics

In classic Doom, the spectre is first encountered on these maps:

Game	ITYTD and HNTR	HMP	UV and NM
The Ultimate Doom	E1M6: Central Processing1	E1M5: Phobos Lab1	E1M3: Toxin Refinery
Doom II	MAP03: The Gantlet	MAP03: The Gantlet	MAP03: The Gantlet
TNT: Evilution	MAP04: Wormhole	MAP02: Human BBQ	MAP02: Human BBQ
Plutonia	MAP02: Well of Souls	MAP02: Well of Souls	MAP02: Well of Souls

The IWADs contain the following numbers of spectres:

Game	ITYTD and HNTR	HMP	UV and NM
The Ultimate Doom	51	102	183
Doom II	37	93	175
TNT: Evilution	83	150	224
Plutonia	95	102	111

1. May be encountered earlier if the secret level is played.

See also

• Partial invisibility issue in Doom95
• Monsters open locked doors