Joven

The math is the joke: tap a fragile legend, sink three more red mana, and you have destroyed one noncreature artifact, the exact thing Shatter did for two mana with no body to protect, no summoning sickness to survive, and no triple-red activation to choke a mana base on. Every restriction here compounds the last. The effect waits a turn for the creature to come online, restricts itself to noncreature artifacts, demands three red mana on top of the cast, and ties the whole package to a legend that any removal answers before it fires. The flavor was the pitch (Joven is a thief and saboteur, and the ability reads as literal machine-breaking), but the rate buried the character under friction no design discipline justifies. What makes the card more than a footnote is precisely how completely it misreads what a tapped, color-intensive, conditionally-targeted ability stapled to a legendary body should cost: it stacks restriction on restriction until a function any common could perform cheaply becomes a five-drop's entire reason to exist. It survives as a useful artifact of how the game once mispriced its own mechanics, before the design language tightened around what a five-mana legendary creature owes the board for the privilege of taking up the slot.