Fiery Tension

When Fiery Tension enters the battlefield,
secretly choose the name of a nontoken creature.
At the beginning of each opponent's end step, if
that player controls an untapped creature with
the chosen name, it's controller sacrifices it. Fiery Tension deals damage to the sacrificed creature's controller equal to it's power.
When a creature with the chosen name leaves the battlefield, sacrifice Fiery Tension.