Ali from Cairo

The effect is a damage replacement: incoming damage that would kill you is rewritten to leave you at 1 instead, which means burn, combat, and any other source measured in damage simply cannot finish the job while the 0/1 body is on the battlefield. Loss of life that does not come from damage walks right through, and so does anything that targets the life total directly or kills you by means other than reduction (decking, alternate win conditions, state-based effects from poison). That gap is the whole shape of the card: a protection effect with a very specific surface area, attached to a creature that dies to a stiff breeze. The design produced a recognizable lineage of "you can't lose while this is around" pieces (Worship being the most famous descendant, with a cleaner condition and a more durable shell), but this is the prototype, and the one whose vulnerability is the point. Removing the 0/1 is trivial; the puzzle the card poses is whether the opponent has the removal or the non-damage finisher in hand at the exact moment the lock would otherwise close. A relic of the era when Magic was still drawing the line between "damage" and "life loss" by hand, before the rules engine had a clean vocabulary for the distinction the card depends on entirely.