I watched something like that about 20 years ago, but I can’t recall the title and it could be from 80s or 90s. It could be TV episode or a low-budget movie.
I only remember a scene, when someone ( a boy? ) was telling a legend his friend about a naked woman who strangled men with her hair ( she was female strangler - a mermaid? a witch? ). It took place on some island, and the legend turned out to be true. It is possible that the boy who mocked the legend was actually attacked and strangled by this supernatural woman. I remember a scene where she was seen with her back to the viewer, completely naked and with very long hair.
It is extremely tough to find. It could be something like Animal X ( TV Series ), so it is hard to find. Thank you in advance.
I found an information that Rosagunde Renaldo (fl. 568) was the first princess of Genovia, so maybe it is good trope. "Rosagunde wore her hair in a long braid, which she used to strangle Alboin". Perhaps it is fictional character, which is connected with other old legend. Strangling with hair is not an uncommon feature in media, e.g., this essay called " The Devouring Woman and Her Serpentine Hair in Late-Pre-Raphaelitism" where there are various characters strangling with hair. https://victorianweb.org/painting/prb/edwards12.html
– wositelec