Bat Wing

Bat Wing (BW) is a Thaumaturgical reagent used on Pagan.

Pagan
Bat wings are used by thaumaturgists to invoke spells pertaining to life and the animal world, as the configuration of flesh, blood and bone within the wings serve as a sympathetic link to the natural sphere. It is unclear if this rare reagent has any connection to actual bats, as the animals do not appear to be native to Pagan. Such wings may only be purchased from the sage, Mythran.

Ultima Online
In Ultima Online, bat wings are used as a reagent in the school of Necromancy.