Goblin Vandal

Three conditions have to line up before this little goblin breaks anything: it must attack, it must connect unblocked, and you must have an extra red mana to spend when the unblocked trigger resolves in the Declare Blockers step, before any combat damage is assigned. Clear all three and the goblin still gives up its damage entirely, so every artifact you kill costs you a turn of pressure. That surrendered swing is what keeps a one-mana body from working as a repeatable Shatter on a stick: the trade is an artifact for a connection, and a defending player who cares about the artifact can simply throw a blocker in front to shut off the trigger before it ever fires. The kill is gated behind combat math rather than the stack, which makes it slow, telegraphed, and trivial to play around in a way that instant-speed artifact destruction never is. The historically interesting part is that red already had clean, resolve-on-the-stack answers to artifacts (Shatter being the textbook one), so this was never red reaching outside its slice of the pie. It was a deliberately worse version of an effect red already owned, bolted onto a creature that has to earn the kill in the red zone, traded down from instant speed to a window the opponent can see coming and stuff with a single chump-block.