Vampfly
The vampire butterfly. One of Taara's blue butterflies, from her swarm, turned when Logi's vampire tooth bonded to it. Thumbnail-sized, dark and wrong-looking among the rest of her swarm, and permanent.

How it was made
Logi took the vampire tooth from Morgantha's body in session 3. It attuned to him, and his hunger for blood-wine grew.
In session 15 Strahd's influence turned Logi into a hostile dire wolf, and he went down unconscious at the wood's edge. Taara found him and pulled the tooth out. It would not go into her pocket. It found the nearest vessel instead, one of her butterflies, and the butterfly took it. It bit Logi on the ear straight away, and has treated this as its purpose ever since.
What it does
- It bites Logi. On the ear, periodically, and on purpose. Its bloodthirst is almost always aimed at him.
- It marks Taara as Strahd's. At the roadside house in session 16 the creatures at the gate recognised what was on her shoulder and waved her through. Logi, with the tooth gone, was turned away: Strahd holds no claim over him.
- It stays. It cannot be given away or sent off. It is comic relief at the table and a real plot thread at once.
In session 31 it came back from Ether with Taara and Logi, to the werewolf den.