AFK Pets and more/Book of Dark Magic

The Book of Dark Magic is a Hardmode wing -type accessory that allows the player to fly and glide. When equipped, they increase the player's Magic damage by 20%. They can also be used as a consumable item, and when it is used, they will give the player the U.N. Owen was her? buff, and it will play a certain song with the same name. It is obtained from Gift Bags after the Moon Lord is defeated.

Trivia
This item is a direct reference to the Touhou character, Flandre Scarlet. The music that plays when the player uses the item is her in-game theme.