Quicksilver Behemoth

Affinity sells a fantasy of casting big bodies for almost nothing, and a 4/5 priced down by every artifact you control delivers on the cheap-beater half of that pitch. The self-bounce is where the deal sours: the moment this Beast attacks or blocks, it goes back to hand at end of combat, every time, no exceptions. That clause turns a permanent into a recurring spell, and the affinity discount stops reading as a bargain and starts reading as the rent you pay to keep recasting something that refuses to occupy the board. As a clock it is hopeless, because a creature that returns to your hand after every attack can never convert pressure into permanence; it pokes for four and resets. The defensive angle is real but narrow, and it is worth being precise about why: returning at end of combat means it stays put through the damage step, so it has to survive on its 5 toughness like any other blocker. If something deals it five or more, state-based actions destroy it before the trigger ever resolves; the bounce saves it from nothing lethal. What it does do is dodge sorcery-speed removal and combat math aimed at killing a smaller wall, then come back to block again the following turn. That makes it a reusable speed bump in a metalcraft shell, not a threat. For an archetype built on sticky, cheap artifacts, a body that insists on leaving is a strange fit.