Gnash, Herald of Death

Whenever Gnash, Herald of Death or another creature you own enters the battlefield under
your control, target opponent sacrifices a
nontoken creature. Then, return that card to the battlefield under your control, except it's a 4/4
black Drone Horror. That permanent is a
creature in addition to its other types.
She roams worlds, slowly draining the life out of them
until they become nothing more than barren
wastelands of undead abominations.