Manticore of the Gauntlet

The enters trigger is built around a tension most aggressive red creatures never confront: it demands a shrink counter go onto something you control before it hurls three damage at a face or planeswalker. On an empty board there is only one legal target, so the reach comes bundled with self-mutilation, leaving the body one point smaller than the printed 5/4. That self-inflicted cost is the whole reason the reach exists: the design pays for a five-mana beater, immediate burn, and a free targeted weakening by making the weakening a liability unless your side is stocked with creatures that profit from being cut down (anything triggering off counters, or fodder you would rather sacrifice than defend). The shrink is the connective tissue to a black-and-red counter-matters school, where reducing your own creatures reads as an enabler instead of a drawback. Set against a vanilla beater at the same cost, this asks you to have already assembled the board it rewards. Outside that build it lands as a slightly awkward attacker with a burn rider attached, which is not nothing, but the trigger is doing two jobs at once and only earns its keep when both have a home.