Contagion Engine 145 (Scars of Mirrodin)

When this artifact enters, put a -1/-1 counter on each creature target player controls. {4}, {T}: Proliferate twice. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

NM - $26.70
LP - $21.30
MP - $16.00
HP - $10.70
DMG - $5.40