Flame of Judgment

The Flame of Judgment is a major plot element in Sonic and the Secret Rings.

Description
When Sonic and Shahra first enter the world of the Arabian Nights, they are attacked by Erazor, and Sonic barely manages to avoid his sword swipe. When he finds out that Shahra has not (and will not) gather the World Rings for him, he shoots a flaming arrow at her as punishment, but Sonic jumps in front of her and takes the hit instead. Erazor then uses the arrow to blackmail Sonic and Shahra into helping him gather the World Rings, promising to remove the arrow if Sonic gathers all of the seven rings for him.

Throughout the game, it is stated that the arrow has cursed Sonic, and that the flame on it is his lifeline; when the flame goes out completely, Sonic will be completely drained of his life energy and die, and only Erazor is able to remove it, as evidenced by Sonic's request to Shahra that she does so. When Erazor summons the Ifrit Golem, the flame is partially out, and it is almost completely out by the time that he gathers all seven.

Apparently, the curse is negated when Sonic is transformed into Darkspine Sonic by the World Rings, as the arrow has disappeared and no mention of it is made again.