Something funny I realised while looking up info about MissingNo is that it's actually... kind of a vaguely cohesive character? At least by glitch standards. It's found in water and one of its only moves is Water Gun, it's classified as a bird and the other move is Sky Attack while one of its forms is Aerodactyl's skeleton, and it clones your items in RB while it clones yourself in Yellow - there's 3 very solid character traits supported by multiple elements of the glitch: it's a bird, it's aquatic, and it has cloning powers.