Bug (1975)
Directed by Jeannot Szwarc; written by William Castle and Thomas Page, from Page's novel The Hephaestus Plague.
Spoilers ahead.
The last film produced by legendary shockmaster Castle turns out to have nearly as outrageous a premise as The Tingler. It takes a while to get going, but things eventually evolve from semi-plausible to completely insane as our story progresses.
We begin in a church somewhere in California. The fire-and-brimstone preacher is going on about America's sinful ways, when an earthquake hits. The scenes of the church being shaken are quite convincing, our first sign that this movie is going to have some visually impressive scenes.
Pretty soon we find out that the quake has opened up a big hole in the ground on a nearby farm. As a son drives his father home from the church, their pick-up truck stalls, then suddenly blows up in a huge fireball. The surviving brother and sister are understandably upset by this.
If you don't know the basic plot of this movie at all, by now you're scratching your head. It's quickly revealed that the big hole has released an unknown species of huge cockroach which has the ability to start fires! Not only do we see them crawl into exhaust pipes and blow up cars more than once, we also see them burn a poor little kitty cat to death.
Our antihero is played by Bradford Dillman. He's some kind of expert in biology. We see him in a classroom making squirrel noises in order to entice a real squirrel into sitting on his shoulder. (Obviously this is a tame pet squirrel, and it's as cute as can be.)
Well, after some scenes of stuff being set on fire, it turns out the bugs can't survive too long, because they're used to the high pressure underground. They literally pop open after a while. End of movie? No, we're barely started.
In a scene which is sickeningly funny, Dillman's wife gets a bug in her hair (wig) and burns to death. This sends the eccentric biologist over the edge. He finds one surviving bug next to the big hole; all the others have exploded. He places this one inside a pressurized diving helmet (!) to keep it alive, then mates it with a plain old everyday ordinary cockroach. This Mad Science leads to a bunch of fire-producing cockroaches that can tolerate the low pressure.
Apparently the whole point of keeping the one bug alive was to have it killed by its offspring, as we see Dillman go into hysterics as the youngsters burn up their progenitor. Unfortunately, these new critters not only have a taste for "raw meat" (and yes, that's going to include human flesh) but, in the movie's most outrageous scene, they apparently share a group mind, and can form words (like "we live") with their bodies!
But that's not all. As we reach the final few minutes of the film, the bugs (who have killed another person, and gone to the trouble of hiding the evidence by dumping her purse in the hole) emerge from the big hole (now glowing satanic red, I suppose from their fire-producing power) with the ability to fly! And they can set off big ground fires while they fly, like some kind of insect napalm. Not only that, but they can smash right through a plate glass window!
You might expect this to be the start of a huge cataclysm of intelligent, flying, fire-producing, flesh-eating bugs, but in fact our movie is over. Dillman falls into the hole after being chased by the bugs, they fall in after him, then another earthquake seals them back in the ground.
Wow. This goofy ending reminds me, in a way, of the nutty climax of The Manitou. Although Bug slows down a bit in the middle, the really excellent insect photography (both real Madagascar giant hissing cockroaches and some nifty models) holds the viewer's attention.