Zii'Griid Berserker

Undying, Double-Strike
If this creature is removed from the battlefield,
summon a 1/1 Black Skull creature tokens.
During an attack phase, if Zii'Griid Berserker is about to be damaged, it's owner may exile any number of Black Skull creature tokens. For each one exiled, grant the attacking creature -1/-0 until end of turn.