Merchant's Assassin

Deathtouch, Flash
When Merchant's Assassin enters the battlefield, target creature an opponent controls gets -X/-X until end of turn where
X is the number of mana from treasure
tokens used to cast Merchant's Assassin.
"Out of range on the roof, detonating those cables
in the shaft, hiding amidst the tarps; this guy
was 3 steps ahead the whole time."