Zombie Fog

A zombie fog looks like a thick patch of mist, 25 feet across per Hit Die. Dogs and horses sense its malice and will do almost anything to avoid it. More obvious are the cadavers that nearly always shuffle along with it, indistinguishable from zombies in their gait, empty faces and decay.

Ordinary attempts to talk to the fog or its cadavers get nowhere. Magical or psionic contact with its mind forces a madness check and still fails.

The fog has no attacks of its own. Its aim is to cause as many deaths as possible within its drifting bulk, and it can steer one cadaver per hit point it currently has.

Up to three times a night it can spread despair: every living creature inside it saves vs. spell or sinks into hopelessness. A despairing victim neither attacks nor defends until struck. That first blow against him gets +4 to hit and ignores his Dexterity bonus to AC; afterward he can fight back, but attackers gain +2 against him and he suffers -2 on his own attacks. Those who save still take -1 to hit for the duration as they struggle against the gloom. Only dawn or dispel magic on the victim ends it.

Normal weapons cannot harm the fog, but magical ones can. Most spells pass through its vapor, except those that stir the air, such as gust of wind, which deal 1d4 per spell level; a 4th-level wind wall, for example, does 4d4.

Barely sentient, the fog prowls by night within a day's travel of a large cemetery or other ample supply of bodies. Sunlight does not hurt it, but it can control cadavers only after dark, so it rarely stirs before sunset.

Every week the fog must feed on at least as many deaths as it has Hit Dice, or it loses a Hit Die for each lean week and may die. Feeding on twice its need in a week adds a Hit Die. Sages suspect it is kin to the mist horror but cannot say how.

Cadavers are corpses puppeted by the fog, not true undead, so they cannot be turned and draw nothing from the Negative Material Plane. Mindless and instantly obedient, they act last each round and strike with whatever comes to hand for 1-6. Ordinary weapons work on them; poison, death, hold and mind-affecting spells do not. A felled cadaver gets back up at full hit points 1-4 rounds later, again and again, until the fog dies or the body is completely destroyed.