Perserverence

Enchant Creature With Power 5 or Greater
{u/r}: If enchanted creature has power 5 or greater, it becomes 4/4 until end of turn.
{u/r}: If enchanted creature is 4/4, it becomes 3/2 until end of turn.
{u/r}: If enchanted creature is 3/2, it becomes 1/1 until end of turn. Add {c} to your mana pool.