A game
You and the house each draw a creature somebody has already discovered. Every card is scored out of ten on its rarity and its twelve traits. Higher card takes the round.
Leave before the last round and the house takes the game.
A card’s number is the average of its twelve traits, and each trait is marked on two things: the creature’s rarity band, worth forty-five percent of every line, and how that trait ranks against the ones a creature of that band could have drawn. So a Common is judged against other Commons rather than against the whole world. A good Common can take a poor Uncommon; nothing takes a Legendary except another Legendary.