Korgos, Tyrant Sorcerer

Hexproof, menace
At the end of your turn, put a soul counter on
Korgos for each creature that died this turn.
Remove X soul counters from Korgos: Exile a
black or red instant or sorcery spell with mana
cost X from your graveyard. You may cast it
without paying its mana cost until the end of
your next turn. It can't be countered.