Alkilith

In the Dungeons & Dragons fantasy role-playing game, the alkilith is an outsider, a demon of the tanar'ri breed. They are sentient blobs of abyssmal pollution and corruption that are used by Demon Lords for missions in the most dangerous and inhospitable regions of the Abyss.

Typical physical characteristics
An alkilith appears as a shivering blob of phosphorescent green corruption surrounded by a cracked, leathery coating that constantly oozes, secretes, hardens, and splits open. Dark, swollen eye-globules dot the surface of its body. Though alkiliths are at least as large as a human, they can shape their amorphous bodies to fit through cracks as small as 1 inch wide. There seems to be no upper limit to an Alkilith's size however; planar travelers tell stories of alkiliths the size of lakes in the deepest reaches of the Abyss. Despite their gelatinous shape, alkiliths can move at a respectable speed.

Society
Even among demons there are those that disgust and terrify; the alkilith is one of these. A shapeless horror used by demon lords for missions in regions most other demons would hesitate to venture into, the alkilith is despised and feared by most other demons. Alkiliths thrive in the foulest and most inhospitable places in the Abyss. They are pollution and corruption made sentient and hatefully alive.

Many alkiliths serve the demon lord Juiblex.

Combat
Alkiliths can attack up to four times a round with pseudopods of acidic slime. These hideous creatures take great pleasure in corrupting and polluting their environs, and they have been known to ignore attackers for a chance to corrupt a pool of fresh water.

In addition to the acidic pseudopods, an alkilith can assume the form of a cloud of noxious green vapor that damages those within it.

Alkiliths also have numerous spell-like abilities, the ability to command oozes, and once per day, they can summon a hezrou.