Dreadpack Cacklefiends

Primal {1}{b}{b}{r} (You may cast this spell for its
primal cost. Spend only mana produced by basic lands
to pay this cost.)
First strike, haste
When Dreadpack Cacklefiends enters the
battlefield, if its primal cost was paid, target
player sacrifices a nontoken creature or discards
a nonland card unless they pay 3 life.