Polymorphist's Jest

A one-sided board wipe that never destroys anything: it lies to the rules engine, redefining every creature a chosen player controls as a base 1/1 blue Frog with no abilities until end of turn. The "loses all abilities" clause carries the whole trick. Indestructibility, hexproof, protection, menace, deathtouch: all of it evaporates, because a Frog has nothing left to fight with. That single stroke turns this into a fog, a removal setup, and an alpha-strike enabler in one window, and the timing dictates which. Cast it on your own attack step and a row of blockers becomes 1/1s that trade down or chump for nothing; cast it on the opponent's swing and the incoming damage shrinks to a trickle. The targeting is the only real restraint: it hits one player's creatures, so it never neuters your own board the way a symmetric sweeper would. The effect is temporary, too, which is the price for the color and the low cost. Note the limit of the trick, though: stripping abilities does not undo an already-active regeneration shield, since that shield is a replacement effect sitting on the game state, not an ability the Frog still owns. You are not killing the threats, only shrinking them naked for a turn, so the reward goes to whoever has the follow-up. Among the polymorph-style effects that win combat by rewriting stat lines rather than removing bodies, few do it this cleanly at instant speed.