Nightmare Heart

Whenever any creature dies, put a +1/+1 counter on Nightmare Heart.

Sacrifice another creature: Regenerate Nightmare Heart.

Dark Ritual - {b}{b}{b} {t}, Sacrifice 3 creatures with the same base power and toughness: If Nightmares Heart is not Indestructible, draw a card. Then if Nightmare Heart has no deathtouch counter, put one on it; if it does, the same for both lifelink and trample counters. If it has all three; double all counters on it, then you may move any number of counters onto another