Certain mythological figures tend to have special magical powers. For example unicorn horns can grant wishes or perhaps gore the crap out of you (as is the case with a few man-made unicorns with horn transplants). Leprechauns have large quantities of gold that somehow we are entitled to steal from them for some reason, when I know a lot of banks with gold that you aren't permitted to steal. It just seems odd as if lack of security entitles one to somebody else's goods. Mermaids have the power to switch between water and land. While on land being indistinguishable from humans. Which raises an interesting evolutionary question, why wouldn't mermaids drive humans extinct if they had the same abilities and then some... it just seems like one hell of a profound advantage. Secondly, they have the magical ability to have their long hair cover their breasts as if by magic (unless something else is covering them). This might actually be an evolutionary reason we aren't all mermaids, specifically that merbabies can't breast feed without getting a mouth full of hair. Just seems like a really odd magical power. For the life of me, I could see no evolutionary advantage for it. If anything it would make breastfeeding harder and negate the roll of breasts as a fertility signal.
Are any mythological figures very evolutionarily sound? Although, the aforementioned real unicorn had a pretty distinct advantage. He quickly realized that with just one big fat horn he could gore the crap out of other animals.