There's a hundreds of themes in horror movies, but one of my favorite ones is when Mother Earth fights back. There's actually a fairly big variety in this theme that began with the 1950s SciFi movies of nuclear outcomes and into the 70s when the polluted earth terrified us. Let's have a look at some of the gems in this genre -
The Day of the Animals
You can find this one on YouTube shown in parts.
You can find this one on YouTube in parts.
Food of the Gods
The Incredible Shrinking Man