The One Ring

Indestructible, singularity (You may only have one
of this card in your deck.)
Equipped creature has hexproof and can't be
blocked. If equipped creature is an Avatar, it gets
+3/+3 and is an indestructible black creature in addition to its other colors and types.
Equip—Pay 3 life unless you sacrifice a nonland permanent or discard a card.