Altar, +of, +Bone (3)
, , Exile a creature you control: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.
As an additional cost to cast this spell, sacrifice a creature.
Search your library for a creature card, reveal it, put it into your hand, then shuffle.
Create a tapped 4/1 black Skeleton creature token with menace. (Then exile this card. You may cast the artifact later from exile.)
Gatherer works better in the Companion app!