Y'ggrosh, the Necrocosm

Trample, lifelink

Eldritch Mastery — When Y'ggrosh, the Necrocosm enters, put a +1/+1 counter on it for
each creature card in all graveyards.

{t}, Remove a counter from Y'ggrosh: Exile target creature card from a graveyard, then create an X/X black Horror Spawn creature token, where X is equal to the exiled card's mana value.