Degeneration
The target’s cells overheat and rapidly degenerate. Each round, at the start of the character’s next turn before they take any actions, they take the listed amount of damage as fire damage and are fatigued. At the end of each of their turns, the creature can attempt a Fortitude saving throw to end the effect; on a failure, cellular degeneration continues but the creature gains a cumulative +1 bonus to the Fortitude save to end the effect.
Source