Gloom Ripper [Lorwyn Eclipsed Promos]

When this creature enters, target creature you control gets +X/+0 until end of turn and up to one target creature an opponent controls gets -0/-X until end of turn, where X is the number of Elves you control plus the number of Elf cards in your graveyard. “I will not rest until I have excised the rot from this land.”