At the end of a round, you may retroactively cancel the effect of a Power that has been used that round. Use once per round.
RavenBlack
Quad Damage
Use once per round: Double all Players' Attack values for this round.
Zarba
Reckless Abandon
Spend 10: Choose an opponent and roll 1d6. The target takes damage equal to 5x the result of the die. Every other Hero takes damage equal to the die result.
Nev the Deranged
Antibody Swarm
Whenever you take damage from an opponent's power directly, remove that power from the game at the end of the round.