The Monolith Monsters

Bill Warren, in his book Keep Watching the Skies, called this one "of the last reasonably serious SF films from Universal." I found it to be on the slow side when I watched it as a kid and not even very comprehensible, but I think that's because it is a bit more adult in nature than the usual with these films. This has an unusual alien invasion - alien rocks that grow when wet; when it rains, that's when it gets really serious, as the alien rocks grow to the size of skyscrapers.

This takes place in one of those desert town locations, a la Tarantula. It all begins with a meteor. A geologist (Phil Harvey) is the first victim of the (currently) small mysterious black fragments of rock. Another geologist (Grant Williams, he who was The Incredible Shrinking Man) finds him in a petrified state. It's eventually discovered that the alien rocks absorb silicon; silica is a substance in human skin which keeps it supple. And, don't get these rocks wet! But, then the rains come... - this is the weird concept: the now-huge rocks topple and the broken fragments grow to new huge monoliths. That's how they move... BoG's Score: 6.5 out of 10
Monolithic Trivia: this film is playing on a TV during an early scene in They Live (1988); John Carpenter may be a fan.