Phase IV was released in the year 1974。Phase IV is also called as Vaihe IV, Sucesos en la IV fase, Phase Four, Phase 4, Fase IV: distruzione Terra, Du tror inte dina ögon。

Desert ants suddenly form a collective intelligence and begin to wage war on the desert inhabitants. It is up to two scientists and a stray girl they rescue from the ants to destroy them. But the ants have other ideas.