Shineshadow Snarl is a rare Land card from Strixhaven: School of Mages Promos (PSTX), collector number 272p. Current market price: $1.53 (foil $3.04), TCGplayer market prices via Scryfall.
As this land enters, you may reveal a Plains or Swamp card from your hand. If you don't, this land enters tapped. {T}: Add {W} or {B}.