Bounding Krasis

Flash is what turns a fair body into a tempo instrument here. Cast at the end of an opponent's turn, the enters trigger taps a would-be blocker so the 3/3 can swing into an open lane next turn; held up during combat, it can tap a fresh blocker to wave your crew through, or untap a creature to bring a surprise blocker into the fray. The tap-or-untap clause reads as Simic value paste, but the timing window is the whole engine: you choose the effect with full information about an attack or a removal spell already declared, which is the difference between a Falter stapled to a creature and a genuine two-for-one. The untap mode also quietly enables ramp tricks (refreshing a tapped mana creature) and pseudo-vigilance (untapping your own attacker after combat, so it stands as a blocker), though those are footnotes next to the combat math. What keeps it fair is that the body is only a 3/3 and the trigger fires exactly once: there is no loop, no recurring lock, just a single well-timed nudge to the board state. That single nudge, delivered at instant speed in two colors that rarely get to push tempo this cleanly, is the design's entire reason for existing.