In some ways, the coming-attractions trailer for The Monolith Monsters is more exciting than the picture itself. The plot gets under way when a meteor crashes in the desert, leaving behind huge black chunks. While being analyzed in a science lab, the crystaline stones are accidentally drenched with water, whereupon they begin to grow to gargantuan dimensions. In a twinkling, these monster monoliths are running amok, "petrifying" whomever and whatever gets in their way. A sudden rainstorm further exacerbates the situation, causing the monoliths to grow to hitherto unimagined heights. Can the world be saved by the saline solution which the scientists are hurriedly developed in the lab? The notion of killer rocks was certainly a novelty: it would have been nice if Monolith Monsters had consistently lived up to the promise of its premise.
~ Hal Erickson, All Movie Guide