Necromancer's Locket

{t}: Add {b} or {w} unless this artifact is equipped to a creature.
{b}{b}{b}{t}: Return target creature from your graveyard to the battlefield and attach Necromancer's Locket to it. Equipped creature has deathtouch and first strike. If the equipped creature dies, exile Necromancer's Locket.
At the start of your upkeep put a -1/-1 counter on the equipped creature.