aka Hercules vs the Hydra
How bad is it? Worse than average swords and sandals fare.
Should you see it? Don't go out of your way, but it's an okay watch.
Jayne Mansfield plays a good queen in a black wig and an evil Amazon in a red wig (there's a purple wig, too) and her real-life husband Mickey Hargitay drools over both as Hercules. The dubbing in this is atrocious and leads to most of the laughs not provided by a three-headed dragon that just stands still while being killed. There are also talking trees of the "Wizard of Oz" ilk and a cyclops.