Mewlips (S."Lincailath") also called Marsh Ghouls or Bog Wights were an evil, semi-legendary race of exceedingly rare, cannibalistic spirits. These shadowy spirits existed to drink blood, which they needed almost as much as other undead needed life-energy. Denizens of graveyards, ruins, and other pleasant sites, they were often found surprisingly near inhabited areas, especially if they had not found much sustenance farther afield lately.
Mewlips were rare even for Undead. Fond of the most noisome and darkest swamps and marshes, they had a silent tread and strangling hands, although they typically used jagged weapons of rusty steel or stone. They were deceptively human in appearance: however, their backs were horribly hunched and their skin shone with a clammy, greenish-brown palor. Even their ragged clothing was moist and foul.
Mewlips fed on most anything and they coveted shiny objects, especially things of gold. It is said that such items reminded them of uncursed life, of the nature of beings not in the thrall of Darkness.
The Mewlips first appear in J.R.R. Tolkien's poem "The Mewlips". The poem is often believed to have been a joke played by professor Tolkien, as the Mewlips appear to be a fictionalized version of ignorant critics who delight on savaging works of literature and cannibalising pitiable authors.