Grim Reaper's Scythe [Marvel Super Heroes Commander]

Whenever one or more creature cards leave your graveyard, create a 2/2 black Zombie creature token.
{3}{B}, {T}, Sacrifice two creatures: Return target creature card from your graveyard to the battlefield with a finality counter on it. Activate only as a sorcery. (If a creature with a finality counter on it would die, exile it instead.)