Swamp Mosquito

Poison spent its first decade as a scattered, vestigial mechanic rather than a deck, and this is one of the small designs where it lived: an evasive attacker that ground out counters one combat at a time, needing ten unblocked swings to close. The 0/1 body is the design tell. It carries no clock of its own and cannot trade up; the only thing it threatens is slow accumulation, which made it a curiosity rather than a kill condition. Flying does the structural work, since the poison trigger keys off being unblocked, and a 0/1 ground attacker would have been chumped forever by any willing blocker. What separates this from later infect designs is precisely the part that kept it harmless: the trigger ignores combat damage entirely and hands over exactly one counter per connection, no matter how big the creature gets. Infect went the other way, tying poison to damage dealt, which is why a pump spell can turn an infect creature into a two-swing kill. Swamp Mosquito has no such ceiling to raise; ten turns of unmolested swinging is a clock no one was ever going to ride to the finish. But the skeleton of the idea (evasion paired with an alternate win condition that bypasses life totals) is the one Wizards kept and eventually got right.