DOOM II (DOOM 2: HELL ON EARTH)

                              GAME MULTIMEDIA FOR
                               GHOST-MONSTER FAQ

                              REVISION 12/09/2006


0. Introduction
1. What Is A "Ghost" In Doom II Games?
2. Where Can I Encounter Ghosts?
3. Which Monsters Can/Cannot Become Ghosts?
4. Can The Ghost Effect Occur Any Other Way?
5. What Affects A Ghost's Movement?
6. How Can Ghosts Be Killed?
7. Can Killed Ghosts Be Resurrected?
8. What Happened To The Ghost I Saw?
9. Will A Surviving Ghost Affect My Score?


o This document provides general information on a bug that can occur in Doom II
  games on various game platforms: The creation of a "ghost" by an Arch-Vile

o This document primarily refers to the PC software package "Doom 2: Hell On
  Earth" version 1.9, and various accurate ports or conversions of this game.
  Other Doom II-based games which are not addressed here (such as Final Doom)
  may be included in future updates.

o This document is 79 characters wide, and is best viewed in a monospaced font.
  The master HTML version is located here: http://classicdoom.com/ghostfaq.htm
  The master text version is located here: http://classicdoom.com/ghostfaq.txt

o Index

o A "ghost" is an abnormal Doom II monster.  It can move freely through some
  solid surfaces, and it is generally immune to a wide variety of attacks and

o A ghost is created when an Arch-Vile resurrects the crushed corpse of a
  monster.  (Corpses are often crushed by doors closing, crushing ceilings or
  rising elevators.)

o Index

o Ghosts may never be encountered during normal game play.  The table below
  indicates map levels where ghosts can conceivably be generated during a
  normal Doom II game.

o Maps where ghosts may be created in PC Doom II v1.9:

                         | Skill | Skill
  Map | Map name         | 1/2   | 3/4/5
  .11.|.CIRCLE OF DEATH..|.Yes...|.Yes..
  .14.|.THE INMOST DENS..|.No....|.Yes..
  .27.|.MONSTER CONDO....|.No....|.Yes..
  .28.|.THE SPIRIT WORLD.|.Yes...|.Yes..
  .29.|.THE LIVING END...|.Yes...|.Yes..
  Notes: In PC Doom II, map 11 is referred to as "CIRCLE OF DEATH" in the tally
  screens, and "'O' OF DESTRUCTION!" in the Automap.
  Map 17, "TENEMENTS", and map 23, "BARRELS O' FUN", are not included here,
  because any Arch-Viles on those maps cannot access areas where monster
  corpses can be crushed.
  Map 30, "ICON OF SIN" is not included here.  Although Arch-Viles may be
  spawned by the Boss entity on this map, monster corpses on this map cannot be
  Note that Xbox Doom II includes additional areas where ghosts may be created.

o Index

o The following monster types can be resurrected as ghosts in PC Doom 2: Hell
  on Earth:

  Zombieman/Former Human
  Shotgun Guy/Former Human Sergeant
  Heavy Weapon Dude/Chaingunner
  Hell Knight
  Baron of Hell
  Pain Elemental
  Notes: A Pain Elemental must be crushed while dying in order to leave a
  crushed corpse behind, otherwise nothing remains to be resurrected.
  Ghost Pain Elementals launch/release normal Lost Souls.

o The following monster types cannot be resurrected as ghosts in PC Doom 2:
  Hell on Earth:

  Lost Soul (cannot be resurrected)
  Arch-Vile (cannot be resurrected)
  Spider Mastermind (cannot be resurrected)
  Cyberdemon (cannot be resurrected)
  Map 31/32 "SS Officer" (no Arch-Vile present)
  Map 32 "Commander Keen" (no way to crush, no Arch-Vile)
  Map 30 "Boss" (no way to crush, Arch-Vile cannot access)
  Notes: A Lost Soul can be crushed while dying, and this can produce a crushed
  corpse; However, crushed Lost Soul corpses cannot be resurrected.

o Index

o While playing a computer-based Doom or Doom II game, an extremely rare
  program error, an "all-ghosts bug", may occur.  This bug can cause all living
  things on the current map to instantly attain "ghost" status, including
  players and some monster types that normally cannot exist in ghost form.

o Index

o A ghost version of a given monster type will move and behave much like the
  normal version of that monster, but with a few exceptions.  Ghosts are immune
  to some of the limitations that affect a normal monster's motion, but remain
  restricted by others.

o The axis of a ghost (an imaginary vertical line running through its center)
  cannot cross through or underneath any horizontal surface that is the "top"
  or "floor" surface of a solid structure or object.  (However, this can still
  allow a ghost to move up to half of its body into most vertical surfaces and

o A ghost may move its entire body through or above any horizontal surface that
  is the "ceiling" or "underside" of a solid structure or object.

o In general, a ghost can move all the way through any part of a structure that
  has no horizontal surfaces.  This can include closed doors, or any wall that
  stretches floor to ceiling (or ground to sky).  If a ghost encounters a
  horizontal surface it cannot cross over or under, it may attempt to go around
  the intervening structure or object, rather than through it.

o Sample ghost movement through solid structures/surfaces:

  One solid pillar | Two pillar sections
  ____ _ _ _ ____  | ____ _ _ _ ____
      :     :      |     :     :
  (|)(|)(|) :      | (|)(|)(|) :
      : (|) :      |     :.(|).:
      : (|) :      |       (|)
      : (|) :      |       (|)
      : (|) :      |      _____
      : (|) :      |     |     |
      : (|)(|)(|)  |     |    (|)(|)
  ____:_ _ _:____  | ____|_ _ _|____
  Notes: The first diagram shows a side view of one wide, floor-to-ceiling
  pillar; The second diagram shows a side view of a similar pillar, with its
  center third removed, effectively making two separate structures; A "(|)" in
  the diagrams represents a ghost Cacodemon.
  The first diagram shows that a ghost Cacodemon can move its entire body
  through any part of this solid pillar.
  The second diagram shows that a ghost Cacodemon can move freely through the
  top section, but can only move about half its body into the sides of the
  bottom section.  (A ghost cannot move its axis beneath any horizontal surface
  that is the "top" or "floor" of a solid structure.)

o The axis of a ghost cannot cross through the axis of a player or a normal
  monster.  The axis of a ghost also cannot cross through the axes of torches,
  barrels, lamps, and similar solid objects.

o Like all walking players and monsters, walking ghosts are limited in how high
  they can climb when taking a single step.  If a normal monster is unable to
  climb up onto a structure, then the equivalent ghost monster will also be
  unable to climb onto that structure.

o Walking ghosts are not inhibited by steep dropoffs.  For example, a normal
  Imp standing on a high ledge or cliff cannot step directly down off the edge;
  a ghost Imp can.

o Ghosts cannot open doors or activate elevators/lifts.

o Ghosts (and ghost corpses) cannot be crushed.

o Ghosts cannot be teleported.  Ghosts do not respond to, or trigger, teleport
  lines or teleporter pads.

o Index

o The following events/attacks can injure or kill ghosts:

  Barrel explosion
  Player rocket explosion
  Imp claw attack
  Demon bite attack
  Spectre-Demon bite attack
  Lost Soul attack
  Cacodemon bite attack
  Hell Knight claw attack
  Baron of Hell claw attack
  Pain Elemental attack (Lost Soul attack)
  Revenant punch attack
  Arch-Vile attack (direct hit or near miss)
  Cyberdemon rocket explosion
  Player teleporting into ghost's coordinates
  Notes: A rocket may not detonate if it touches a ghost; but if the rocket
  detonates against a solid object, any ghost within range of the explosion can
  be affected.
  A completed Arch-Vile attack affects the target and a small area around the
  target; A ghost can be harmed anywhere within this region.
  A ghost can be "telefragged" like any normal monster: If a player teleports
  to a ghost's location, the ghost is killed.  (Ghosts normally cannot be
  telefragged by other monsters in PC Doom 2: Hell on Earth.)
  Note that normal-monster weapons will auto-aim as usual when used on ghost
  monsters, but player weapons will not.
  Some events/attacks listed above may not affect ghosts if the "all-ghosts
  bug" is in effect (see question 4).  For example, an exploding rocket can
  fail to cause damage if it was fired by a ghost player.

o As with normal monsters, ghosts can be destroyed through the use of "mass
  kill" cheat codes.  (Such codes exist in Doom 95, and in other third-party
  "source ports" of the original Doom engines.)

o The following events/attacks/projectiles generally do not injure or kill

  Player punch attack (normal and Berserk strength)
  Player chainsaw attack
  Player bullets (pistol and chaingun)
  Player pellets (both shotgun types)
  Player rockets (unexploded)
  Player plasma (plasma rifle and all BFG-9000 emanations)
  Zombieman/Former Human bullets
  Shotgun Guy/Former Human Sergeant pellets
  Heavy Weapon Dude/Chaingunner bullets
  Imp fireballs
  Cacodemon fireballs
  Hell Knight fireballs
  Baron of Hell fireballs
  Arachnotron plasma
  Revenant missile (homing and non-homing types)
  Mancubus fireballs
  Spider Mastermind bullets
  Cyberdemon rockets (unexploded)
  Notes: In general, the events/attacks/projectiles listed above will have no
  effect on any ghost; However, a very narrow area at the base of a ghost's
  vertical axis can sometimes be affected by some of these attacks.  (For
  example, plasma bursts will pass through nearly all parts of a ghost
  Cacodemon, but may also occasionally impact a point near the base of its
  axis, causing damage.)
  A rocket may not detonate if it touches a ghost; but if the rocket detonates
  against a solid object, any ghost within range of the explosion can be
  A homing Revenant missile fired at a ghost will usually pass through the
  ghost (or miss) and may then circle back repeatedly in an attempt to strike
  the target.
  Note that normal-monster weapons will auto-aim as usual when used on ghost
  monsters, but player weapons will not.

o Index

o A killed ghost can be resurrected any number of times by an Arch-Vile.  When
  resurrected, the monster remains in ghost form.

o When monster respawning is in effect (through a Respawn switch or parameter,
  or through the built-in respawning effect of Nightmare Skill), a killed ghost
  will respawn as a normal monster.

o Index

o Ghosts may disappear for a variety of reasons: Sometimes a ghost may move out
  of the level entirely, and wander beyond the borders of the map; Walking
  ghosts can become stuck in pits or trenches that normal monsters cannot step
  into; Sometimes ghosts get stuck behind objects, or get stuck in parts of
  structures that they cannot move all the way through; When a ghost is killed,
  its corpse may fall into or through a wall, where it cannot be seen.

o Index

o In Doom 2: Hell On Earth, any ghost monsters created by Arch-Viles have
  already been killed at least once, and the "KILLS" score in the tally screen
  will reflect that.  Failing to kill a ghost created by an Arch-Vile will not
  subtract points from the score.

o Index

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