Invisible Invaders is noteworthy for being a pre-George "Night of the Living Dead" Romero example of zombies in formal-wear stalking the Earth and killing the living. Here, they're inhabited by invisible aliens who can also take over dead bodies. And they have a plan.
What is the plan? Kill everyone on Earth.
Thankfully, the always intrepid John Agar as an Army Major teams up with three intrepid scientists to come up with a weapon to use against the aliens. They work fast. That's good because apparently the Moon was once like Earth until the aliens beat the Hell out of it thousands of years ago.
The acting is earnest but inept. The visual effects are pretty much all either laughable (why do the aliens drag their feet when they're invisible, leaving a very clear trail?) or stock footage of things crashing, blowing up, or burning down. I'm pretty sure the only clear shot of a UFO flying has been lifted from Earth vs. The Flying Saucers. Oh, well. Invisible Invaders also has a whole lotta narration, I'm assuming to bolster its attempts to look like a documentary. Strange, bad, enjoyable stuff. Recommended.