Breaking Wave

Most untap effects pick a side: yours untaps, theirs stays put, and you exploit the asymmetry. This one refuses to choose. It flips every creature's tap state on the board at once, untapping what was tapped and tapping what was untapped, so it cuts in either direction depending on whose turn it is and what the board looks like. Cast on your own turn after attackers have been declared and tapped down, it readies your team to block a swing-back instead of staying exposed; cast on an opponent's turn through the flash clause, it taps down a fresh army that was about to alpha-strike, leaving them defenseless into your counter-swing. That optional flash cost (pay two more to cast it any time you could cast an instant) is the whole engine, converting a clumsy sorcery into a combat-warping ambush priced as a tax on wanting the timing. The effect is global and unconditional, which is what disciplines it: it touches your creatures too, so you cannot fire it carelessly and expect a clean tempo swing. And because tapping a creature does not pull it out of combat once it is already attacking, the window that matters is the gap before attackers are declared. That makes this less a removal answer than a precise piece of combat-step manipulation, the kind of card that rewards reading the math several steps ahead of the swing.