Whispering Darkness

+1: Target creature without shadow gains shadow. You may pay 2 black mana. If you do, destroy target creature with shadow.
-1: Distribute up to 2 -1/-1 counters among any number of target creatures. Each creature targeted this way gains shadow.
-6: You get an emblem that says "When you or a creature you control takes damage, deal 2 damage to target player or creature with shadow".