Unite the Coalition

The all-color mana cost is the toll, and everything downstream is about spending it well: five modes off a menu, repeatable, aimed wherever you need them. What separates this from the usual charm-style modal spell is that the repetition is unconstrained. Nothing stops you from choosing "deals 2 damage to any target" five times for ten damage split across a board, or five card draws, or five separate phase-outs to blank an entire battlefield for a turn. The design leans on the assumption that assembling all five colors is itself the cost being paid, so once you clear that bar the payoff is deliberately unfenced. That phase-out mode is the sharpest tool in the kit, and the most quietly nasty: phasing out a permanent removes it as a blocker, an attacker, and a target without triggering leaves-the-battlefield abilities or handing an opponent a death-trigger, and it returns under their control next turn as if nothing happened. A five-color instant that can protect your own board, strip an opponent's, and burn a player out in the same cast is a lot of rope, which is why the color requirement does the balancing rather than any per-mode restriction. It reads as a five-color payoff written for tables where fixing every color is the whole deckbuilding project, and the reward for solving that project is a spell with almost no wrong answer at instant speed.