Ensnared by the Mara is a rare Sorcery card from Doctor Who (WHO), collector number 84. Current market price: $7.28 (foil $7.99), TCGplayer market prices via Scryfall.
Each opponent faces a villainous choice — They exile cards from the top of their library until they exile a nonland card, then you may cast that card without paying its mana cost, or that player exiles the top four cards of their library and Ensnared by the Mara deals damage equal to the total mana value of those exiled cards to that player.