Nergaliid

Nergaliids, the Devil Toads are rotund, scaled, frog-like devils from the Nine Hells, but sometimes found in Xhorhas. A nergalii named Kylre worked with The Fletching and Moondrop Traveling Carnival of Curiosities, posing as a lizard man, to secretly feed on old and infirm people brought to him by Gustav Fletching.

Description
Nergaliids are corpulent and covered with scales. They avoid the direct contact with society and prey away from prying eyes, getting their norishment from the life force of unsuspecting cretures usually while they sleep, which gives them terrible nightmares. If the victim uncovers nergaliids, nergaliids offer to strike a deal, proposing to give material wealth in exchange for freedom and silence. Devil toads only attack the target, if an accord seems unlikely.

According to the book The Fiends of Folklore, nergaliids were alleged to feed on people in the night while they slept. Their ability to drain life from those around them can also allow for their victims to be transformed into mutilated, zombified corpses, whose skin and muscles fell away, leaving a shambling set of bones and organs that attacked without much visible intelligence.

Abilities
Nergaliids are resistant to cold damage; bludgeoning, piercing, and slashing nonmagical attacks that aren't silvered. They also immune to fire, poison damage and immune to poisoned condition.

While in dim light or darkness, the devil toads can take the Hide action as a bonus action, as well as having an increased a long jump up to 30 feet and a high jump up to 20 feet, with or without a running start. Nergaliids can lash its tongue at their target, dealing bludgeoning damage, and bite one creature, dealing piercing damage and spreading poison. Siphon Life (recharge 4-6): The nergaliid magically draws the life from a humanoid it can see within 40 feet of it. The target must make a DC 15 Wisdom saving throw. An incapacitated target fails the save automatically. On a failed save, the creature takes 10 (3d6) psychic damage, and the nergaliid gains temporary hit points equal to the damage taken. On a successful save, the target takes half as much damage, and the nergaliid doesn't gain temporary hit points. If this damage kills the target, its body rises at the end of the nergaliid's current turn as a husk zombie.

Trivia
The nergaliid creature and stat block was created by Matthew Mercer for Critical Role, drawn from classic demonology and ancient religions.