Mewlip

Mewlips are minor spirits found in old fens and swamps. They are aggressive, evil level ~11-12 mobiles who are incorporeal and cannot be bashed. They load with 1 silver and 3 copper.

A mewlip is here, faintly wailing at you.
> look mewlip
It is a pale shape floating in mid-air, about the size of a human torso with
faint limbs. Its glance is cold and lost, and its voice seems to come from
the very bottom of the swamps.