I'm a happy little dwarf with my new pet.
It is a [Captured Firefly] pet, and drops from Bogflare Needlers in Zangarmarsh. It took me a total of 586 kills to get it.
The item flavor text says: "Still flying..." This is a reference to the television show, Firefly. The quote from the show that the flavor text was taken from goes as follows:
Mal: We're still flying.
Simon: That's not much.
Mal: It's enough.
Edit: I uploaded a quick and dirty video of the animation.
Edit2: The only sound it makes is a little background hum of its wings.
Edit3: Yes, this pet is new as of patch 2.1.0.