Maze's Mantle

A flash pump aura that only unlocks its rider when the target already carries toxic: that gate is the entire design. Cast at the wrong moment or on the wrong body, it settles for a +2/+2 with the ambush upside every flash aura enjoys. Cast in response to targeted removal on a poison creature, it becomes a two-for-one that dodges the spell, saves the enchantment's tempo cost, and leaves a bigger clock on the table, all in one instant-speed window. Green already owns instant-speed protection through effects like Snakeskin Veil and Tyvar's Stand, so the interesting choice here is not that green gets hexproof but that the aura withholds it, refusing to protect anything that isn't a toxic threat. The +2/+2 does not touch the poison math (toxic applies its fixed number of counters no matter how large the creature swings), so the buff is purely a combat lever: a bigger body to push regular damage or trade up, not a way to deal more poison. That division of labor is honest about what the card is: connective tissue for a poison-counter deck rather than a standalone spell. The buff and the conditional hexproof both serve the same goal of keeping a fragile toxic plan alive through the exact removal step that would otherwise blow out an aura's investment.