Can you explain the mystical power of the “femme fatale”?

A good friend of mine came to visit last night and we started to talk about a couple of women we know that could only be classed as “Femme fatales”. Here

I have had this conversation before, due to a particular woman who has caused “havoc” in other peoples relationships by running off with the man and subsequently changing his whole personality. Meaning a stable guy, who was sensible with money suddenly, was spending like crazy in order to please her. Her main train of thought is that “Men are here to look after me”

They do and for long extended periods of time. While we normal dull females do all the usual things, love the guy, care about him, and contribute to a relationship. She simply asks and gets. I know her well, in the sense that she was married to someone very close to me for ten years. He too, was butter in her hands. Totally contradictory to his regular personality. All the men she meets are different completely so you cannot deduce that they had a fatal flaw she played upon.

Of the two females one is considered very attractive, and this one alternates between being attractive and very unattractive depending on her lifestyle at the time.

We decided she has some sort of chromosome or gene that is universally appealing coupled with a pheromone that men cannot resist! However I searched femme fatale and I see these women have been around since history began, in both folklore and myth.
“She is an archetypal character of literature and art. Her ability to entrance and hypnotize her male victim was in the earliest stories seen as being literally supernatural, hence the most prosaic femme fatale today is still described as having a power akin to an enchantress, vampire, female monster or demon.” Some known femme fatales include Cleo Patra and Mata Hari

Have you been the “victim: of a femme fatale? What were her powers over men? I do believe this is the only term I can give to these particular women today. Thoughts?