The Fact Checker is a rare Legendary Creature — Human Wizard card from Unknown Event (UNK), collector number RZ03j. Current market price: $15.18, TCGplayer market prices via Scryfall.
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.