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Invuln sphere map08

An invulnerability found in Doom II MAP08: Tricks and Traps.


A view of Hell Revealed MAP14: City in the Clouds after obtaining an invulnerability.

The invulnerability is a powerup that makes the player generally impervious to damage for 30 seconds, found in all classic Doom games. The player is not protected from telefrags, and will still recoil from a successful attack. The powerup looks like a green sphere with a grinning red-eyed head inside. While it is active, the colors in the player's display change to inverse monochrome, and the eyes of the status bar face glow yellow (STFGOD0), making them look similar to the Demon's; in the last few seconds the display will begin blinking back to its original colors. While the inverted monochrome effect is activated the game is effectively fully bright, and the player will be able to see every detail even in the darkest areas. Spectres in particular become much easier to see under its effects.

Invulnerability can also be activated with the cheat code idbeholdv.

In deathmatch mode of vanilla Doom, invulnerabilities and blur artifacts never respawn. Some source ports allow flags to be set to cause them to respawn.

Invulnerabilities are included in the items percentage displayed at the end of each level.


According to the function P_DamageMobj in p_inter.c, invulnerability only protects the player from attacks doing less than 1000 points of damage; while no monster in the game can do nearly that much damage in one attack (a direct hit from the rocket of a Cyberdemon will inflict at most 288 damage), a telefrag inflicts 10000 points (and indeed will kill even an otherwise invulnerable player). This also means that DeHackEd can be used to circumvent the invulnerability powerup by creating incredibly powerful weapons.



The early invulnerability powerup, as seen in MBF's emulation of the Doom press release beta.

  • The grinning face inside the sphere appears to be derived from the Lost Soul sprite in Doom 0.4. Oddly enough, the invulnerability sphere in that version of the game was invisible and had an unused sprite in the IWAD which looked like a giant health bonus.
  • Due to limitations of the Doom engine, an Invulnerability Artifact lights up all the areas in the game similar to the Light Amplification Visor. It would require a complete table of 32 shades for a proper effect.
  • Interestingly, although a damaging floor of Type 11 will cancel the effect of the God mode cheat, the invulnerability artifact will remain active while the player is in such a sector until its proper duration has expired. This property of the artifact would theoretically allow players who obtain one using the idbeholdv cheat to buy enough time that they can clear out ending Type-11 rooms containing monsters, such as the one in Phobos Anomaly.

Data Statistics[]

Ultimate Doom 16 15 16
Doom II 29 24 23
TNT: Evilution 15 13 12
Plutonia 5 5 5

See also[]