Malvoren [Unique Abomination]

Malvoren was a bastard son of a merciless warlord and a born sorcerer, so talented that the warlord's own master, the maimed lich-god, took notice. Too young to know that outshining his father was fatal, he was walled alive in a tomb with his books. There, overconfident, he tried a spell beyond him, and it twisted him into the Thing in the Shaft: a slime-slick mass of hundreds of tendrils, nameless and soulless, craving only others' pain.

Each round 2d6 tendrils strike at up to four targets as far as 40 feet away. Anyone hit by four or more in one round is caught, held helpless, and crushed for 2d6. The Thing drags captives in 10 feet per round. Mouthless, it does not eat; it squeezes the victim into its mass until dead, then tosses the body aside. Escape means severing each gripping tendril (4 hit points apiece) or making a Strength check for each one.

Its coating of ooze makes it fireproof, and charm, control, and form-changing magic such as polymorph does not affect it.

It lives alone in its tomb. If released, it would haunt any dark place large enough, from alleys to wells and cellars, silently terrorizing anyone who comes near.

A monster scholar would likely find it akin to the roper, perhaps a legacy of the failed spell. It needs no food, sustained only by hatred and humiliation, and kills from cruelty rather than hunger.