If you would guess a card, instead just choose the outcome you want. At the beginning of each opponent's upkeep, look at the top card of their library. Tell them the name of that card. They tell you its mana cost, type line, power, and toughness. Then reveal that card. If they got anything wrong, draw a card.
Near Mint - $17.900
Lightly Played - $14.300
Moderately Played - $12.500
Heavily Played - $10.700
Damaged - $8.900
Near Mint Spanish - $17.900
Lightly Played Spanish - $14.300
Moderately Played Spanish - $12.500
Heavily Played Spanish - $10.700
Damaged Spanish - $8.900