The heroes would obliterate the villainess, but lose to a pure-energy form.
Bomp, bomp, bomp-bomp-bom-bomp,
PURE ENERGY.
I'll tell you what first freaked me out about the '78 film: the POSTER. I was 8 years old when it came out and it gave me the screaming heebie-jeebies. This was before I even knew what the damn thing was about...