Ulamog, Hiverazer

When Ulamog, Hiverazer enters the battlefield exile all creatures you control with converted mana cost 3 or less Sliver creatures you control have annihilator 1 (when this creature attacks, defending player chooses one permanent to sacrifice) Sliver creatures you control have devoid{flavor} Ulamog’s forced assimilation into the hive didn’t come without it’s costs