After the death of Franco, Spanish cinema went all out with sex and violence, like a big explosion. Many of the films of the period are not very good save for the titillation, but this little horror jewel is. It's creepy, sleazy and without a dull moment, even when it's clearly made as a quick exploitation cash in of the Satanist successes of the period (even the original Spanish poster is a blatent rip-off of famous illustrations). A B-movie done right.