Tidewater Minion

An untapper stapled to a wall, built so the engine outlives the wall. The repeatable : untap any permanent is the part that has launched a thousand combos, from infinite-mana rocks to reusing tap-down lands and creatures, and the design knows it: this is why the body wears Defender. A 4/4 frame would be a problem if it could swing, so the card pays for its untap loop by sitting still, then offers a buyout. For you shed Defender until end of turn, which means the wall is not a permanent jailer but a tariff: a combo deck gladly leaves it home behind blocks, while a deck that has run the loop to its conclusion can simply cash in the body and attack. That two-stage structure, a tapped-down combo piece that converts into a finisher, is rare among the era's plainer untappers, which gave you the loop but no way to close with it. The design problem here is an old one: how do you hand a player a repeatable untap effect without also handing them a free attacker? The answer is to gate the clock behind mana you would rather spend on the combo itself. The untap targets any permanent, not just artifacts or lands, which is the quiet breadth that keeps it relevant: it powers whatever engine you already have rather than asking you to build around a narrow trigger.