Demonlord Kyolfephex

Sacrifice a creature: Demonlord Kyolfephex gains Deathtouch, Haste, and Menace until
end of turn. If the sacrificed creature was Legendary, Demonlord Kyolfephex gains Massacre 10 (When 10 or more creatures are on
the field, including yours, destroy those creatures. They can't be regenerated).