- "A chunk of pure, crystallized monster malice. Often obtained from monsters who possess the power to curse."
- — In-game description
Evil Crystals are items from The Legend of Zelda: Skyward Sword. They are dropped by enemies capable of Jinxing Link such as Cursed Bokoblins, Dark Lizalfos, and Dark Keese. They can also be found in chests or randomly dropped by Gossip Stones, and are one of the two possible prizes for making 20 - 27 slices in the Clean Cut mini-game, the other reward being a Monster Horn.
Link can bring Evil Crystals to the Scrap Shop in the Bazaar in order to upgrade his equipment. Evil Crystals are used to upgrade the Bug Net and the Bow. Evil Crystals can be sold to Rupin for 30 Rupees each on certain nights.