Void Squall

Five mana to bounce a single nonland permanent is a price no tempo deck would pay outright; what justifies it is rebound, which turns one Boomerang into two on consecutive turns for the cost of a single card. The first cast happens now, the spell exiles itself as it resolves, and your following upkeep offers a free second bounce off the top of your sequencing. That second swing is the real design: it converts a clunky, overcosted unsummon into a recurring tempo lever that strips an opponent's best permanent twice across two turn cycles, often timed to undo whatever they redeployed in between. The catch is the window. The rebound cast only fires from exile on your own upkeep, on your own clock, so it can never answer a threat the moment it lands; you pay full retail for the privilege of bouncing on a schedule rather than on demand. That makes it a card built for the grind, not the race: it wants a board where buying time twice matters more than buying it once cheaply, and where the opponent has a permanent expensive enough that returning it twice actually costs them tempo. The whole structure trades the flexibility of a cheap instant for the inevitability of a delayed second hit, a fair-but-slow bargain in a color that rarely gets to run bounce as a recurring engine rather than a one-shot reset.