The Day of Justification

All Ponies, Pegasi, Unicorns and Alicorns have
+1/+1.
At the end step of each turn, if a Pony, Pegasus, Unicorn or Alicorn has died this turn, you may sacrifice another creature.
If you do, you destroy 1 creature, then you gain
life equal to the destroyed creatures power.
If there are no creatures on the battlefield,
sacrifice this enchantment.