Wall of Ice

Seven toughness is the whole design, and the number is chosen with surgical intent: it blanks the era's red burn and walks off most early creature damage without trading, which is exactly the structural job green wanted its wall to do. Buy turns, not threaten back. This was the green entry in Alpha's original wall cycle, where each color got a defender sized to its philosophy, and green's came in at a flat 0/7 for three mana. The cost curve tells the same story: three mana for seven toughness was an aggressive rate when it was printed and remains a generous one by modern math; the design tax is the body's complete inertness, with no activated ability, no triggered upside, no ramp rider, just a wall. Later sets would iterate hard on this template (Wall of Blossoms turned the slot into a cantrip, Wall of Roots turned it into a mana source, Overgrown Battlement turned it into a payoff), and each of those iterations is legible as a response to what this card declined to do. The original is the baseline the green defender archetype was built against: pure toughness, pure tempo, no tricks.