Telltale Heart

Whenever a creature dies, for each creature that
dealt damage to that creature this turn, its
controller sacrifices it or pays 3 life.
{b}{b}, Discard a card or sacrifice a creature:
Target opponent sacrifices a creature unless they
pay 3 life.
"Villains!" I shrieked, "dissemble no more! I admit the
deed!-tear up the planks!-here, here!-it is the beating
of his hideous heart!"