Vampiric Mist

A vampiric mist is a dense, rolling cloud 5 to 8 feet across. Hungry, it is pale pink; full, it glows deep crimson. It reeks of stale blood, and that smell usually arrives first. It has no language but communicates through a limited telepathy.

Warm-blooded prey within 50 feet is always sensed, and the mist takes the shortest path, flowing through cracks and over water; only nonporous barriers stop it, and it is smart enough to find a way around.

Each round it reaches out with one misty tendril. Targets are treated as AC 10, adjusted only for Dexterity and magical protection (rings, armor bonuses and the like), never magical shields. A hit drains 1d8 points of blood. If the attack roll beats the number needed by 4 or more, the mist envelops the victim and hits automatically every round until it dies, finishes feeding or withdraws. Allies striking an enveloping mist split their damage evenly between the mist and the victim; only the victim can attack it safely, and the dizzying blood loss prevents the victim from using spells or devices that need concentration. Sated mists still drain in self-defense, dumping the surplus.

Ordinarily only magical weapons and air-affecting spells harm it, though lightning bolt and magic missile also work. When it reaches full hit points it becomes substantial for 1d6 turns: movement 6, AC 8, and ordinary weapons can hurt it.

Track two numbers for each mist. Its maximum begins at 24 (it has 8 hit points per die when full, though it is rarely met that way) and every wound lowers both the maximum and its current total. Each 2 points of blood it drains restores 1 current hit point, never above the reduced maximum, so feeding is not true healing. Starvation costs 1 current hit point per 12 hours unfed, and reaching 0 from any cause kills it. After the fight, a survivor's maximum returns to 24.

They haunt swamps, hidden in dawn and dusk fog, and pitch-dark caverns, hunting at night or early morning. They prefer lone prey, but a starving mist may raid a village, killing livestock and draining sleepers before slipping away at sunrise.

Long thought to be young crimson deaths, they are now known to be the creation of a mighty vampire wizard. A mist reproduces by splitting, with a 10% chance during its substantial phase right after a meal. Each offspring has 3 Hit Dice at 4 hit points per die, born starving.

They feed on all warm-blooded life. No animal hunts them, but leeches, stirges and similar bloodsuckers drawn by the smell sometimes die trying. A vampiric mist has no natural life span; it lasts until it starves, is destroyed or divides.