Suncrusher

The keyword's clearest mascot: a colorless construct that pays you, in counters, for every color of mana you squeeze into its cost. Spend all five and it lands as an 8/8; spend the bare colorless minimum and it shows up as a 3/3 whose two abilities sit idle for lack of fuel. That reward structure is the whole tension, because the counters are not just a body but a shared resource for both activations: a removal effect that destroys a creature, and a self-bounce that returns it to hand. Every kill you fire shaves a counter off the toughness, so the more you point it at the board, the smaller and more fragile it gets, until the bounce lets you recast it and refill from scratch (assuming you can assemble five colors of mana twice). That recursion loop is what gives it staying power past the fixed-stat artifact beaters of its era: a self-replenishing removal battery whose ceiling is gated entirely by how greedy your manabase can afford to be. The artifact-creature type keeps the colorless casting cost honest, since the card never demands colored pips even as it begs for colored mana. It is the cleanest demonstration of why this keyword was built for five-color decks: a card technically castable anywhere and only worth casting where the rainbow runs deep.