The Loreley's Grasp
Las garras de Lorelei (original)
The legendary Loreley has been living for centuries in a grotto beneath the river Rhein in Germany. Every night when the moon is full, she turns into a reptile-like creature craving for human blood. When one girl after another of a nearby boarding school is killed by her, a hunter named Sirgurd is engaged to kill the monster.
Starring Tony Kendall, Helga Liné, Silvia Tortosa, Josefina Jartin, Loreta Tovar, José Thelman, Luis Induni, Francisco Nieto, Betsabé Ruiz, Luis Barboo
Watch "The Loreley's Grasp" from streaming services Amazon, Tubi TV released in 1974. It's a fantasy and horror movie, and has a rating of 5.7 out of 10 from Imdb which is fairly okay for this kind of movie.