Vargouille

Vargouilles are floating Neutral Evil heads with bat wings and small floppy tentacles. They own a shriek effect to paralyze nonvargouilles within 60 feet. Their origin is lower-planar so those planes, and areas where those planes are meddled-with, are the most likely places to find them.

The signature attack (and mode of reproduction) is to kiss you on the lips (muah!), clearly easier if you already can't move. This, failing a saving-throw, passes on a disease: over time, your head takes on vargouille traits until, at the end, the body is shunted aside and the head floats away.

The vargouille might seem to gargoyles as jermlaine to gremlins: some Frenchified way around a public-domain term such as to make it not public. In this case the second Monster Manual attempted more creativity. And it's under the OGL anyway so D&D and Pathfinder parties can enjoy this old-school monster together.

Monte Cook seems inordinately fond of it. The Vargouille Knife is a bane in the Banewarrens of Ptolus; if you hit someone with it, his/her head turns into this. Also there's a plane in Beyond Countless Doorways where vargouilles flit around swapping bodies.