Since ancient times, frog is the emblem of cowardice, ineptitude, folly, conceit, annoying chatter (of their croaking) and thus also the emblem the slander, it is even libidinous, and due to that it is a fertility symbol. Its ugliness is the external feature of its inferior soul. It's a demonic and anti-demonic creature, and yet we see a frog prince in this tailless amphibian that can make itself at home both on land and in water, so it can freely choose its habitat.