Fistful of Force

Two mana buys you +2/+2 at instant speed and a peek at the top of two libraries, which is the floor here; the ceiling depends on a mechanic that paid players to lie about their curve. The reveal rewards a deck top-heavy enough to flip a higher mana value than the opponent, an incentive that pulls against the aggressive shells that most want a cheap pump spell to begin with. That friction is the whole personality: a deck built to win the reveal is rarely the deck that needs the trick, and a deck that needs the trick is rarely built to win the reveal. Take the flip and the pump doubles to +4/+4 with trample, enough to bury a chump block or close a race outright. The library look is the part most players treat as incidental: revealing the top card and choosing top or bottom is a small selection effect attached to every cast, worth something even on turns the flip goes the wrong way. Against Giant Growth, the comparison that frames it, this trades a flat, dependable boost for a variable result plus a card-selection rider; a player who wants a guaranteed answer will reach for the deterministic option, while one comfortable gambling on their own deck gets a trick that still offers a card-selection rider at its floor and ends games at its ceiling.