Blade Feathers

Exploration Stage: Post Office
From: Mr. Black
Description: I couldn't make out how exactly the monster was moving, but it might have wings. I picked up some strange feathers not far from where I saw the silhouette. They should be around here, find them.
Completed: You can check for yourself but the monster's feathers look like blades. I'm not sure if they're meant for flying, but they'd certainly make a terrible weapon.