This seldom-seen, well-crafted monster movie involves the reopening of a Utah silver mine which had been closed for nearly 70 years after a catastrophic cave-in, the circumstances of which remain one of the nearby town's most legendary mysteries. When attempts are made to explore the mine shaft, the investigating party never returns. It seems the mine's collapse had served to seal in a nest of weird, multi-tentacled, bloodsucking creatures -- which are now free to seek new prey on the outskirts of town. This simple but intense horror film benefits from good performances and genuine suspense -- providing only quick, spooky glimpses of the title beasts -- building to a thrilling showdown in the treacherous mine shafts.