Damping Sphere is a uncommon Artifact card from Dominaria (DOM), collector number 213. Current market price: $0.75 (foil $5.65), TCGplayer market prices via Scryfall.
If a land is tapped for two or more mana, it produces {C} instead of any other type and amount. Each spell a player casts costs {1} more to cast for each other spell that player has cast this turn.