knowledge that lives rent free in my mind: some species of bats predate upon smaller bats. hoaries in particular have been known to attack pipistrelles even during periods of insect abundancies (Karl A. Shump, Ann U. Shump, Lasius cinereus, Mammalian Species, Issue 185, 23 November 1982).
hoaries are also extremely fluffy. possibly the fluffiest bat in north america.
so, the idea of a rogue flier with the appearance and physical traits of a lasiurus cinereus could be a very effective predator of unaware or too-trusting people in the underland. and any missing people could be blamed on other denizens of the underland. who would suspect a flier? especially one so fluffy?
lasiurus species, not just hoaries but all of the lasiurini, are also known to use their fluffy tails as blankets, curling up and sheltering their front, with only their heads and maybe a bit of their chest remaining exposed. a lasiurini flier could offer such as a hammock, especially to Overlanders not used to living underground, away from the warmth of the Sun. It just so happens that that might put an unlucky individual's head in biting range, and once that individual dozes off...
i bestow this cursed information upon you to do with as you wish.
It's perfect and I will cherish this forever. Cannibal fliers and human predating fliers go into the worldbuilding.
