When Phyrexian Devourer's power is 7 or greater, sacrifice it. Exile the top card of your library: Put X +1/+1 counters on Phyrexian Devourer, where X is the exiled card's converted mana cost.
Near Mint - $20.80
Lightly Played - $16.70
Moderately Played - $14.60
Heavily Played - $12.50
Damaged - $10.40
Near Mint Spanish - $20.80
Lightly Played Spanish - $16.70
Moderately Played Spanish - $14.60
Heavily Played Spanish - $12.50
Damaged Spanish - $10.40