Tormenting Echoes

As an additional cost to cast this spell, sacrifice X nonland, nontoken permanents.
Choose target creature, player, or planeswalker. Tormenting Echoes deals X damage to it if it's
the target of exactly one spell named Tormenting Echoes.
Gravestorm (When you cast this spell, copy it for
each permanent put into a graveyard this turn, you
may choose new targets for the copies.)