Giant Spider

Two power for four mana is a deliberate underpayment; four toughness for four mana is a deliberate overpayment, and the gap between them tells you exactly what this body is for. It is priced to trade up against fliers rather than to race anything, and that stat line encodes a design law green has lived under since the beginning: the color is not allowed to fly, but it must be allowed to interact with the sky, so it gets a grounded creature with extra toughness and permission to block upward. The ability later got named Reach (early printings spelled the function out longhand), but the function was here from the start, and it established the rate that subsequent green anti-air creatures were costed against. Every cheaper or more efficient version since (Sentinel Spider, Penumbra Spider, and the leaner reach bodies that eventually made this exact card obsolete) is essentially a discount on this baseline. The card itself is no longer a serious play anywhere, but its design fingerprint sits on the entire green creature suite that followed: a humble template that quietly defined what green is permitted to do against the air.