Fistful of Force (LRW-212) - Lorwyn

Target creature gets +2/+2 until end of turn. Clash with an opponent. If you win, that creature gets an additional +2/+2 and gains trample until end of turn. (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.)