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 Foil - $70.90
Lightly Played Foil - $67.40
Moderately Played Foil - $63.80
Heavily Played Foil - $56.70
Damaged Foil - $46.10
NM-Mint Foil Non English - $70.90
Lightly Played Foil Non English - $67.40
Moderately Played Foil Non English - $63.80
Heavily Played Foil Non English - $56.70
Damaged Foil Non English - $46.10