Enrage the gods

Take power from the gods to bend time to your will. Roll a d20, if you roll a nat 20 then you are permitted to change any and all events in the past up to 5 rounds if in combat or, if out of combat, 24 hours. If you fail the roll the GM punishes you by giving you any curse they wish as long as it does not cause permanent death. The curse cannot be dispelled by any means other than those that the GM personally allows.