Boxed Shadow

When Boxed Shadow dies, tap each creature
target player controls without a soul counter
on it, then remove a soul counter from each
untapped creature that player controls.
{2}{b}{b}: Sacrifice Boxed Shadow.
The surrounding blackness was darker than any
starless night, so dark that Eric felt as if he was
suffocating, as if he could drown right then and
there with his feet on the ground.