Ghost's in Doom 2 Please Read

[Guest mancubas]

Please read the FAQ provided below--------------------------

0. INTRODUCTION
===============
o This document provides general information on a bug that
occasionally surfaces in computer-based Doom II games:
The creation of a "ghost" by an Arch-Vile monster.

o This document primarily refers to the software package
"Doom 2: Hell On Earth", version 1.9. Other Doom II
games which are not addressed here (such as Final Doom)
may be included in future updates.

o This document is 59 characters wide, and is best viewed
in a monospaced-font format.

o Index

1. WHAT IS A "GHOST" IN DOOM II GAMES?
======================================
o A "ghost" is an abnormal Doom II monster. It can move
freely through some solid surfaces, and is immune to a
wide variety of attacks from players and other monsters.

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

o Index

2. WHERE CAN I ENCOUNTER GHOSTS?
================================
o Ghosts may never be encountered during normal game play.
The chart below indicates map levels where ghosts can
conceivably be generated during a normal Doom II game.

o Map levels where ghosts may be created in 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..
.16.|.SUBURBS..........|.No....|.Yes..
.20.|.GOTCHA!..........|.Yes...|.Yes..
.25.|.BLOODFALLS.......|.Yes...|.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 gain access to areas where monster corpses can be
crushed.
Map 30, "ICON OF SIN" is not included here. Although
Arch-Viles may be generated by the Boss entity on this
map, monster corpses on this map cannot be crushed.

o Index

3. WHICH MONSTERS CAN/CANNOT BECOME GHOSTS?
===========================================
o The following monster types can be resurrected as ghosts
in Doom 2: Hell on Earth:

Zombieman/Former Human
Shotgun Guy/Former Human Sergeant
Heavy Weapon Dude/Chaingunner
Imp
Demon
Spectre-Demon
Cacodemon
Hell Knight
Baron of Hell
Arachnotron
Revenant
Mancubus

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

Lost Soul (leaves no corpse)
Pain Elemental (leaves no corpse)
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)

o Index

4. CAN THE GHOST EFFECT OCCUR ANY OTHER WAY?
============================================
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

5. WHAT AFFECTS A GHOST'S MOVEMENT?
===================================
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 objects.)

o A ghost may move its entire body through or above any
horizontal surface that is the "ceiling" or "bottom"
surface 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 one wide, floor-to-ceiling
pillar; The second diagram shows a similar pillar, with
its center third removed, effectively making two separate
structures; A "(|)" 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 another live 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

6. HOW CAN GHOSTS BE KILLED?
============================
o The following events/attacks can injure or kill any
ghost:

Barrel explosion
Player rocket explosion
Imp scratch attack
Demon bite attack
Spectre-Demon bite attack
Lost Soul attack
Cacodemon bite attack
Hell Knight scratch attack
Baron of Hell scratch 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 will 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 cannot be telefragged by other monsters.
Note that normal-monster weapons will auto-aim as usual
when used on ghost monsters, but player weapons will not.

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 various third-party "source ports" of the
original Doom engines.)

o The following events/attacks/projectiles cannot injure or
kill any ghost:

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: A rocket will 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.
While Revenant missiles cannot touch a ghost, a homing
Revenant missile will continue to attempt to strike the
ghost, unless/until it strikes something else, or the
ghost is killed by some other force.
Note that normal-monster weapons will auto-aim as usual
when used on ghost monsters, but player weapons will not.

o Index

7. CAN GHOSTS BE RESURRECTED AGAIN?
===================================
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

8. WHAT HAPPENED TO THE GHOST I SAW?
====================================
o Ghosts may disappear for a variety of reasons: Sometimes
a ghost may move out of the level entirely, and wander
around outside 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

9. WILL A SURVIVING GHOST AFFECT MY SCORE?
==========================================
o In Doom 2: Hell On Earth, any ghost monsters that appear
have already been killed at least once, and the KILLS
score in the tally screen will reflect that. Failing to
kill a ghost will not subtract points from a KILLS score.

Pretty Freaky S**t

[Lüt]

What, you've never seen this before?

[Guest ZarcyB]

F*ck off

[TheProphet]

Once I really spotted a ghost in the Suburbs level (in "normal game play"). I was in the first room again, because outside was too much action.
Suddenly this imp came through the wall, and when I noticed that I couldn't even hurt him with my Super Shotgun, I immediately quit Doom. I admit that I found this monster a bit scary.

[Lüt]

ZarcyB said:

F*ck off

Calm... take the needle out of your eye and rest for a few hours.

[Lüt]

TheProphet said:

Once I really spotted a ghost in the Suburbs level (in "normal game play"). I was in the first room again, because outside was too much action.
Suddenly this imp came through the wall, and when I noticed that I couldn't even hurt him with my Super Shotgun, I immediately quit Doom. I admit that I found this monster a bit scary.

I had that happen in one of my earlier maps - it was a just-for-fun secret level I made that was a descending spiral - you get a chainsaw and there's about 1,000 pistol guys to work your way through. They teleport too. I'd occasionally get it so that, after enough ammo clips were dropped (ones which I didn't pick up), the entire population of the level (the remaining 500 guys) became ghosts. It was a little unfair when you get a blob of 500 invincible guys walking through walls and eachother, hunting you down.

[TheProphet]

Heh, sounds like a good challenge :-)

[Guest Duke Nukem]

Lüt said:

What, you've never seen this before?

I havent. Can it only occur in doom2.exe?

[NiGHTMARE]

What? That must mean you've never played Requiem, one of the coolest add-ons ever...

[Guest Lament]

Ghosts don't appear in ZDooM. :(

Bring back the ghost bug! Whoo!!!