So I was fighting Chaos on DoS again, with a slightly different party setup to what I normally use (I swapped one Red Mage for one White Mage, essential in the DoS version as Chaos has 20,000 HP instead of 2,000) when I noticed that the cute little metallic flashes appearing over the enemy as I attacked were pointing out something very odd.
The red square is essential: Without it you wouldn't see what I was pointing out. Isn't that clever?
Chaos appears to be giving birth to a bird, although Garland was definitely male before transforming into this thing. I'm sure people have noticed it before but discuss anyway.