The Shirt Button is a Rare Boss that appears on Stage 10, along with The Waffle.
Appearance[]
As the name says, the boss resembles a blue shirt button. There are purple threads crossing the middle.
Pattern[]
The Shirt Button spins slowly in one direction. It then repeats this process, but in the opposite direction, and so forth.
Knives[]
Already spawned knives: 0
Knives to put: 20
Strategy[]
No particular strategy is required here.