Evil Eye of Orms-by-Gore

Designed as a puzzle box rather than a creature. The two restrictions point in opposite directions: the controller can only attack with Eyes (vanishingly rare, especially when this was printed), while the opponent can only block with Walls (which historically cannot attack at all). The result is a 3/6 body that wants to go to the red zone alone, against a defense that structurally cannot stop it, while the rest of your board is forbidden from following. The card is a closed system: it solves its own combat math by forbidding everything around it. That design idea (a beater whose drawback is shouldered by every other creature you play, and whose evasion is paid by every blocker the opponent might raise) is the kind of thing early design did openly and modern design routes around with keywords like menace or protection. It also produced one of the genuine oddities of the early game: a tribal lord with no tribe, an attacker whose own army cannot march behind it. The Eye creature type sat essentially unused for years afterward, which means the card's first restriction was, for most of its life, a flat prohibition on attacking with anything else. The flavor of a singular monstrous eye that demands the battlefield to itself is doing real work here; what looks like rules text reads instead as flavor expressed in mechanics.