Frostboil Snarl is a rare Land card from Strixhaven: School of Mages Promos (PSTX), collector number 265p. Current market price: $1.14 (foil $3.00), TCGplayer market prices via Scryfall.
As this land enters, you may reveal an Island or Mountain card from your hand. If you don't, this land enters tapped. {T}: Add {U} or {R}.