Read a lot of fairy tales, and you will find the that the Mad Scientist used to be the Mad Ogre/Witch/Sorcerer/Devil, with a beautiful daughter (well, several daughters, but if more than one was significant, only one was good, and perhaps only that one was beautiful). Who might be in the habit of turning into a bird (though generally dependent on a feather-skin to do so) but certainly was the best thing to happen to the prince in her father's power, since she knew how to counter her father's magic.
Meanwhile I'm working on a story where superpowers come from the experiments of Mad Scientists. (Would explain the laughter. A long history of cackling.)
But, of course, where do Mad Scientists come from?
At the moment, the one front and center is the granddaughter who's inherited a fairly mild book of effects from her grandmother, who used to be a doctor in a traveling show (and who even has a clue about why sometimes it produces horrible powers and distorted people). BUT -- I don't think I can make it completely hereditary, since I also have an evil laboratory full of people working evil experiments on consenting victims. For all of them to descending from wizards and witches of old -- hmm, might work, but I might have to work out something about skipping generations and the like, because otherwise everyone would be a Mad Scientist.
Which is obviously unfeasible, since a hard-and-fast rule is you can be a Mad Scientist and give powers, or not, and get them, but you can't be both.