Web

Reach did not exist as a keyword in early Magic, so the ability to block fliers had to be granted the long way: stapled onto a one-mana Aura cast on a creature. That is the structural problem this card solves. The reach effect itself was not foreign to green at the time (Giant Spider carried it printed directly onto its body in the same set), but Web exists to hand that same answer to a creature that lacks it: an Aura that retrofits "can block flying" onto any ground body, one at a time, with a +0/+2 to sweeten an otherwise conditional answer to a board state that might never arrive. The cost structure tells the whole story of the design tension: cheap enough to slot in, narrow enough that committing to it was a gamble, and card-disadvantageous the moment the opponent simply killed the host. Modern green creatures get reach printed directly on the card, usually alongside other relevant text, which retired this slot decades ago. What survives here is a snapshot of the color pie being assembled one Aura at a time, before keywords like reach were abstracted out of the spells that granted them and folded into the creatures themselves.