Bloody Spine

The Bloody Spine is a consumable item used to summon the Brain of Cthulhu while in the Crimson. It can be crafted at a Crimson Altar or a Demon Alter from Vertebrae dropped by Blood Crawlers, Face Monsters, and Crimeras. Attempting to use it outside the Crimson will have no effect and will not consume the item.

Trivia

 * While it is the counterpart of Worm Food, the Bloody Spine is actually easier to make, since it does not require anything besides Vertebrae