Alucarda (1978)

Orphaned Justina moves into a convent where she shares a room with Alucarda, a strange girl who immediately gloms onto Justina and forms a suicide pact with her within the first day. They are cared for by the nuns, who look like mummies due their heads being wrapped in bloody bandages.

Alucarda and Justina gallavant through the forest and run into a hunchback gypsy, who ends up involving them in a satanic ritual which at first appears to be a dream sequence. They also play in an old tomb, where Alucarda opens a coffin and releases howling evil. The girls commence to swear their allegiance to Satan during the holy readings, which leads to an exorcism in which Justina is accidentally killed, and Alucarda conveniently forgets about their suicide pact.

This movie has lots of blood and naked women, but mostly it has screaming. Lots and lots and lots of screaming, which continues through the entire movie. At first its annoying. Then it becomes so ridiculous that it's funny. But by the end of the movie, it's intensely annoying and drives you almost to the point of insanity.

The dvd cover features a creepy looking image of Alucarda - very nicely done.