Razor Boomerang

Equipment that fires itself off the creature it sits on, and the whole design lives in that unattach effect. The granted ability costs plus unattaching the boomerang; on resolution it deals its single point of damage and then returns to your hand rather than dropping detached onto the battlefield. That bounce-to-hand is the recurring tax. To throw it again you recast the artifact for three and re-equip for two, a five-mana loop every time you want another point of reach. That overhead is what keeps a repeatable damage source from settling into a turn-after-turn machine gun; the math punishes anyone treating it as free reach. The single point reads small, but the source matters more than the number. Because the damage comes from a creature's activated ability rather than a spell, it sidesteps the counterspells and spell-based hate that answer a burn card. The throwable structure also gives the artifact a kind of resilience few pingers have: it sits on the battlefield as Equipment, unbothered by creature wraths, and even a targeted bounce or destruction can be played around by activating it in response, sending it home before the answer resolves. The flavor and the mechanic move in lockstep in a way few Equipment manage: a boomerang that comes back to your hand is exactly what the return-to-hand text describes, the rare case where the rules language reads like the object it names. Slow and mana-hungry as reach, but the structural idea (a recyclable, throwable damage source any creature can wield) is cleaner than the rate suggests.