Grants a Rotten Heart upon use. If Isaac has an empty red heart container (or empty bone heart), the rotten heart will fill it. If Isaac has red hearts and/or bone hearts but no empty container, it will replace one of its red hearts. If Isaac doesn't have red or bone hearts, it has no effect.
Synergies[]
Book of Virtues: Creates green-glowing rotten hearts wisps on the middle ring. They spawn a Blue Fly when shooting, similar to Rotten Baby. The wisps also create a small green cloud when destroyed, which is purely cosmetic.