Ring of Xathrid (M13-215)

: Regenerate equipped creature. (The next time that creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's black.
Equip (: Attach to target creature you control. Equip only as a sorcery.)