Vacuum Quasi-Elemental Original Stats
I'll start with the Second Edition version:
Quasielemental, Negative - Vacuum
CLIMATE/TERRAIN: Quasiplane of Vacuum
FREQUENCY: Uncommon
ORGANIZATION: Band
ACTIVITY CYCLE: Any
DIET: Anything
INTELLIGENCE: Low to high (5–14)
TREASURE: Nil
ALIGNMENT: Neutral
NO. APPEARING: 1d6
ARMOR CLASS: –1
MOVEMENT: 36
HIT DICE: 6, 9, 12
THAC0:
6 HD: 15
9 HD: 11
12 HD: 9
NO. OF ATTACKS: 1
DAMAGE/ATTACK: 1d4 + 1hp/HD
SPECIAL ATTACKS: Draw air
SPECIAL DEFENSES: See below
MAGIC RESISTANCE: Nil
SIZE: S (4′ tall)
MORALE: Champion (15–16)
XP VALUE:
6 HD: 2,000
9 HD: 5,000
12 HD: 8,000
While some greybeards like to categorize these creatures as the embodiment of the destruction or absence of air, a truly canny blood knows the real dark — vacuum quasielementals embody the absence of everything. The things’re completely invisible, and their shape is that of an amorphous, rubbery, hollow skin.
COMBAT: A vacuum quasielemental can ram foes with its shapeless body, inflicting 1d4 points of damage plus 1 additional point per Hit Die (6, 9, or 12). But more importantly, it also draws any surrounding air into itself. An area of 60 feet around the creature is treated as though a continual gust of wind spell blew toward the quasielemental. Any air-breathing sod within the area automatically suffers 1d4 points of damage per round — the monster literally sucks the breath away from him. (‘Course, this doesn’t apply on an airless void like the Quasiplane of Vacuum.)
If in a confined space, a vacuum quasielemental can reduce a 60-foot cube of air to a vacuum within a single round. However, it can maintain the airless state for only 10 rounds; it must then stop and rest for an hour before using this power again.
Like all quasielemental beings, vacuum quasielementals can be struck only by of +1 or better weapons. Air-based spells (such as gust of wind) cast by a wizard or priest of a level higher than the quasielemental’s total Hit Dice slay the creature if it fails a saving throw versus death magic.
HABITAT/SOCIETY: Vacuum quasielementals are surprisingly gregarious creatures, gathering in small groups whenever possible to converse and interact. On the other hand, they have no love for any other beings and usually attack intruders on their quasiplane. Like their cousins of salt, vacuum quasielementals prefer to remain on their home plane. Sure, every elemental creature feels a certain level of discomfort when in an alien environment, but vacuum quasielementals actually dislike using their absorption abilities, which physically tire them.
ECOLOGY: Much about vacuum quasielementals remains dark. Fact is, no one really knows how they sustain themselves; it’s just conjecture that they feed upon the air they draw into themselves. They may not need anything at all to survive. Or perhaps, like the strange egarus fungi also found on the Quasiplane of Vacuum, the creatures literally survive on nothing — that is, nothingness.
Originally appeared in Planescape Appendix III (1998).
And here's the original First Edition version:
VACUUM QUASI-ELEMENTAL
FREQUENCY: Very rare (Common)
NO. APPEARING: 1 (1-6)
ARMOR CLASS: –1
MOVE: 36″
HIT DICE: 6, 9, or 12
% IN LAIR: Nil
NO. OF ATTACKS: 1
DAMAGE/ATTACK: 1-4 + 1 hp/HD
SPECIAL ATTACKS: See below
SPECIAL DEFENSES: See below
MAGIC RESISTANCE: See below
INTELLIGENCE: Low
ALIGNMENT: Neutral (chaotic)
SIZE: S
PSIONIC ABILITY: Nil
LEVEL/X.P. VALUE: VII/1,000 + 15 per hp
Vacuum quasi-elementals are the living embodiment of a nullity — the absence of elemental Air. They are invisible by nature, though if their presence is detected (by detect invisible, true sight, etc.), they appear as amorphous, three-dimensional “skins” of force (similar to an ochre jelly in zero-gee).
Vacuum quasi-elementals suck in any and all surrounding air, seeking to reduce any area of confinement to the the same level of airlessness as their native plane. In the Prime Material plane, the region within 60′ of a Vacuum quasi-elemental has the effects of a gust of wind spell blowing toward the quasi-elemental. A Vacuum quasi-elemental can reduce a 60′ × 60′ area to vacuum in a single round. Those within an area so vacated of air suffer the effects of being in the plane of Vacuum (no loss of pressure or temperature, only the absence of air itself). In addition, those caught within this range who require air for survival suffer 1-4 hp damage per round in addition to any attacks made by the creature.
In regions of abundant air (such as the Prime Material plane), Vacuum quasi-elementals can cause their air-removal effects for 10 rounds at most, after which they cannot do so again for one hour. When overwhelmed by air, these quasi-elementals become spherical in shape, and their armor class increases to AC –4. They may still attack normally (ramming a target with their forcelike bodies), but cannot use their special attack.
Air-using spells can destroy a Vacuum quasi-elemental only if the level of the caster (or hit dice of the monster) is greater than that of the Vacuum quasi-elemental. If attacked in such a fashion, the Vacuum quasi-elemental is allowed a saving throw vs. death magic; if this succeeds, it is unharmed by the attack. If the saving throw fails, the Vacuum quasi-elemental is destroyed. A gust of wind cast by a 1st-level magic-user has no effect on a 6-HD Vacuum quasi-elemental, but a 7-HD djinn could destroy it. Vacuum quasi-elementals are subject to magical attacks, but require + 1 or better magical weapons to be damaged.
Nature may abhor a vacuum, but magic-users find these airless creatures useful as both protectors and laboratory aides (they may provide an environment without dust by removing the air that keeps the dust suspended). As such, they are valued when encountered on the Prime Material planes. This rarely occurs, as most which survive are those locked in some airtight compartment which they have drained of air, or (it is rumored) in the spaces between the planets and stars.
Originally appeared in Dragon #128 (Dec 1987).