I confess that I haven't seen the 1957 SHE-DEVIL in over 20 years, and haven't found even a greymarket source for a copy. Thus I won't review the film here, but I will link to this review at DVD Savant.
This seems to be the ultimate-- in the sense of "the last"-- adaptation of Stanley Weinbaum's short story, "The Adaptive Ultimate." I suspect that the short story's appeal to film, radio and television may have been that its "monster" was simply a woman who changed from less-than-attractive to a bombshell, in this case played by popular B-actress Mari Blanchard. The fact that the monster needed no more than a basic Hollywood makeup job probably made it attractive to producers than its loose adaptation of Stevenson's "Jekyll and Hyde" trope. Still, SHE-DEVIL does deserve to be known as one example of the comparative wealth of femmes formidable- films that appeared during the 1950s decade.
One interesting addition to the standard adaptation of "Adaptive" is a memorable scene in which Kyra, having married a wealthy man, simply does away with him by crashing their car. Her powers enable her to survive the wreck while he perishes, while the apparent circumstances give her a great murder-alibi. Amusingly, the footage of the car-crash was lifted from an earlier femme formidable film of the period, 1952's ANGEL FACE.