Trial of Zeal

Burn sold as an enchantment instead of an instant, with a rebuy clause bolted on. The first trigger does the obvious thing: three damage on entry, the same output as any baseline three-damage spell. The second trigger is the whole design. Drop a Cartouche onto one of your creatures and this returns to your hand, ready to redeploy for another three the next time you have the mana. That reusability is the pitch, and also the leash: recursion fires only off the narrow event of a Cartouche entering, so the payoff lives inside a specific package of cheap aura buffs rather than any red deck wanting reach. Every cycle resets to sorcery speed, too, since the damage lands only when the enchantment re-enters, never at instant speed when combat math wants it. Among the Trial-and-Cartouche pairing this one is the simplest to weigh, because removal is removal: a repeatable kill spell or face-burn engine for a deck built to keep bouncing it back. The loop hides a real mana tax, though; each redeploy spends a Cartouche plus three more to recast the Trial, so the "reusable" burn is only reusable at full retail price each time. Strip the aura shell away and what remains is a three-mana enchantment that does a one-mana spell's job once, then sits on the battlefield as inert cardboard.