Skullitis is a disease that is inflicted when someone is shot in the head with the Dying Will Bullet 10 times. The person then dies after 2 hours. Skullitis makes small black and white skulls show up on different parts of your body and those skulls reveal your deepest secrets out loud until you die. Because of this, it is also called the "Shame to Death" disease. The opposite of this disease, which Shamal used to heal Tsuna, is the Angel Disease, though its effects are unknown.