When Contagion Engine enters the battlefield, put a -1/-1 counter on each creature target player controls. {4}, {T}: Proliferate, then proliferate again. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)
NM-Mint - $23.10
Lightly Played - $22.00
Moderately Played - $20.80
Heavily Played - $18.50
Damaged - $15.10
NM-Mint Non English - $23.10
Lightly Played Non English - $22.00
Moderately Played Non English - $20.80
Heavily Played Non English - $18.50
Damaged Non English - $15.10