Bigfin Bouncer

Man-o'-War's descendants have been arriving at four mana for years, and this is the plainest of them: a body, a tempo swing, and nothing else asked of the pilot. The four-mana cost on a 3/2 buys a creature that resets an opponent's board development while adding to yours, the classic tempo trade where you spend a card and mana to buy a turn rather than to answer a threat permanently. The bounce is aimed strictly at what an opponent controls, so there is no cute self-bounce line to reload another enters-the-battlefield trigger; play it on curve, against something that hurts to recast. What limits the effect is that it fires exactly once from a fragile body: the 3/2 dies to almost anything, and the tempo it bought does not come back once the creature has traded. That fragility is also the entry point for players who want more from it, since any effect that returns this creature to hand and replays it converts the one-shot bounce into a recurring tempo tax on whatever the opponent tries to develop. On its own, though, this is common-rarity blue tempo built to the oldest template in the color: put a threat on the board, and set the opponent back a beat while you do it.