Donuts

Donuts are a currency in Book of Monsters which can be spent in the Donut shop. They are currently not usable as the Donut shop is unreleased. They can be obtained by an Event Pass, or completing a Gameplay Achievement.

Donuts will likely be used to buy Monster Costumes and Minions, because there is a Cosmic Minotaur skin and a Chicken Minion inside the Donut Shop, which is likely a hint at what the Donut Shop will sell.