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The parameters are not restored upon resurrection, so all such pools of blood are potential ghosts ''if'' the original monster has a resurrection sequence (a set of sprite pointers usually containing the frames of the death of the monster in reverse). Most [[monsters]] have one, with the [[lost soul]], [[arch-vile]], [[cyberdemon]], and [[spiderdemon]] being exceptions.
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The parameters are not restored upon resurrection, so all such pools of blood are potential ghosts ''if'' the original monster has a resurrection sequence (a set of sprite pointers usually containing the frames of the death of the monster in reverse). Most [[monsters]] have one, with the ones that cannot be resurrected by the [[arch-vile]] ([[lost soul]], [[cyberdemon]], [[spiderdemon]] and another arch-vile) being exceptions.
   
 
==Notes==
 
==Notes==

Revision as of 10:04, 26 February 2010

This article is about the bug in Doom II. For information about the Heretic monster type, see Ghosts (Heretic)

A ghost monster is a monster with unusual ghost-like properties. This is caused by a rare bug that occurs when the monster's corpse becomes a small pool of gore by being crushed under a door or ceiling and is then resurrected by an arch-vile. The ghost monster looks normal and still behaves like before being killed, except that it retains some of the properties of the pool of gore it had become. When moving, these properties allow it to pass through walls to sectors that are equal to or lesser in height in respect to the one it occupies. As far as combat is concerned, the ghost monster can usually only be harmed by splash damage, monster melee attacks, arch-vile attacks, and telefragging. Nonetheless, since its near-immunity to some attacks occurs because it cannot be aimed at, it is possible to harm it by hitting a specific, very narrow area at the base of its axis with a regular projectile attack, although this is very difficult to achieve.

Some PWADs have used the ghost monster phenomenon as a feature, such as The Waterfront, Requiem's MAP23: Hatred, Icarus: Alien Vanguard's MAP24: The Haunting, Hell Revealed's MAP26: Afterlife, Hell to Pay's MAP14 and MAP22, and Plutonia 2's Map 32: Go 4 It.

As with many Doom engine bugs, this one is fixed in various source ports, although in some of those it can optionally be enabled. In ZDoom, this is enabled for the aforementioned maps, but cannot be selected otherwise.

In extremely rare cases, a memory overflow can occur which causes all things, including players and monsters, to become ghosts. In deathmatch play, this phenomenon is termed the DM no-clipping bug. One such way to cause this is when a hitscan attack, including BFG tracers, crosses over more than 128 linedefs/things at once.

thumb|300px|right|Here is a video including "Ghost Monsters"

Technical

The following code creates small pools of gore:

P_SetMobjState (thing, S_GIBS);

thing->flags &= ~MF_SOLID;
thing->height = 0;
thing->radius = 0;

The parameters are not restored upon resurrection, so all such pools of blood are potential ghosts if the original monster has a resurrection sequence (a set of sprite pointers usually containing the frames of the death of the monster in reverse). Most monsters have one, with the ones that cannot be resurrected by the arch-vile (lost soul, cyberdemon, spiderdemon and another arch-vile) being exceptions.

Notes

  • The pain elemental specifically has a resurrection sequence, yet normally leaves no corpse to resurrect. If one is crushed to death or while dying, however, a pool of gore is generated. This means pain elementals can only be resurrected as ghosts.

Demo

See also

External links