Erithizon

Wizards built this as a designed downside, and the downside is the whole point. A green four-drop that should be a clean beater instead hands the defending player a counter every time it swings: they choose which creature gets bigger, and they choose it on your attack step, so the buff lands before blocks. The effect is a slow-motion liability that compounds. Each attack feeds a blocker that can either wall the next swing or grow into a threat of its own, and because the defender picks the target, you cannot even aim the counter at something irrelevant. This kind of almost-good creature with a parasitic catch was a common design language in green's early years, before power creep made unconditional stats cheap. What keeps the card from being purely self-defeating is that the drawback hangs entirely on the attack trigger: hold it back and the body sits there as a dormant 4/4, which means you opt into the penalty rather than having it forced on you. That gives the card a strange home in builds that want to feed an opponent's creature on purpose: Donate-style giveaway shells, or group-hug tables where growing a board is the social contract. Those are deliberate abuses of a clause meant to punish. As printed, the defender choosing where the counter lands is the rare case of a green creature whose attack step can improve your opponent's board instead of yours.