Wave of Terror [Weatherlight] - 86

The sea of fear has endless depths.

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) At the beginning of your draw step, destroy each creature with mana value equal to the number of age counters on Wave of Terror. They can't be regenerated.