Broken Ambitions is a common Instant card from Lorwyn (LRW), collector number 54. Current market price: $0.35 (foil $6.19), TCGplayer market prices via Scryfall.
Counter target spell unless its controller pays {X}. Clash with an opponent. If you win, that spell's controller mills four cards. (Each clashing player reveals the top card of their library, then puts that card on their choice of the top or bottom. A player wins if their card had a greater mana value.)