Infernal Possession

When Infernal Possession enters the battlefield,
Choose a creature card in a graveyard. As it
enters the battlefield, it gains "Champion a
creature that shares a creature type with this
card." until it leaves the battlefield, then put it
onto the battlefield. Infernal Possession becomes
an aura with "enchant creature". Attach it to that
creature. When Infernal Possession leaves the
battlefield, that creature's controller sacrifices it.