Korgore, Town of Death

All black creatures you control have +10/+10.
Whenever a creature dies return it to the battlefield under your control and search its owners library for a creature card and put it in
the graveyard.
{t}: Kill all creatures except this one, chose 5 and return them to the battlefield under your control.
{t}: Add {b}{b}{b}{b}{b} to your mana pool.