This is mod is unreleased because it's not finished.
The mod intercepts calls to SpriteBatch.Draw, determines which frame of a sprite of an NPC/animal/monster/etc is being drawn, and overlays a hat onto the thing's head. Unreleased because each frame of every sprite requires configuration of where to put the hat because the head position changes. This is a ton of work and I only ever completed it for Penny. The framework is ready to use though - just missing configuration.