Polarities Mod/Skulduggery Unpleasant

Skulduggery Unpleasant is a Pre-Hardmode book that is purchased from the for  after Skeletron is defeated. When used, it provides the player with 72 defense for a single hit, and taking that hit will remove the added defense for three minutes. This timer is hard-coded, cannot be refreshed by removing the buff and re-using the book, and is shared with.

Trivia

 * Its title is a reference to the fantasy novel series Skulduggery Pleasant.