The Living Storm

Bestow {3}{u}{r} (If you cast this for its bestow cost, it enters the battlefield as an enchantment attached to target creature, when it is unattached, The Living Storm becomes a creature.)
Haste, Double Strike.
Enchanted creature has +4/+2, haste, Double Strike, and "When this creature leaves the battlefield, this creature deals 2 damage to target creature or player."