Freezing arrow

Cast Freezing arrow only if you control a legendary scout or a Arien planeswalker.
Freezing arrow cost{2} less if you control a Arien planeswalker.
Creatures in target opponent control get -3/-3 until end of next turn.
If a creature will die this way exile it instead.
This let the name freeze because the air arround becomes cold, but is pure negative energy.