Risen Riptide

A 0/5 that contributes nothing to the clock on its own, its entire offensive value outsourced to a keyword it never generates itself. The trigger reads on cast, not resolution: every time you pay a kicker cost, the creature becomes a base 5/5 until end of turn. That timing is the whole trick. The toughness never dips below five, so the defense is constant, but the power only shows up on turns you actually spend the kicker payment, and it lasts the full turn rather than blinking away when the spell resolves. Cast a kicked spell during your own combat and the body swings as an attacker for that turn; cast one on a defensive turn and it can trade up against something it was built to eat, holding at 5/5 through the whole exchange. When the kicker payments stop, it reverts to a stonewall. This is a rider on an incentive that lives elsewhere, closer to how prowess bodies cash noncreature spells than to any standalone beater: it asks a deck to run enough kickable spells that the trigger fires reliably, and supplies none of them. The rate is deliberately lopsided (excellent defense, zero base offense) so the offense arrives only as a bonus on mana you were spending anyway. That is a clean way to hand a defensive body a real ceiling without letting it set the pace on its own.