Alien invasion movies are usually downright hilarious, while only some are intentionally so. Unintentionally funny movies from this genre may cause critics to throw tomatoes at the directors, but don't listen to the critics. Do the opposite of what they tell you to do and watch the following films.
"Killer Klowns from Outer Space"
Grant Cramer and Suzanne Snyder play Mike and Debbie, two teenagers who witness the landing of a circus tent full of alien clowns that feed on human flesh. These clowns track down humans with balloon animal dogs and kill them with wacky contraptions. The cops and townspeople don't believe the alien clown story until one is arrested and kills everyone in jail. Luckily, a team of meddling kids in an ice cream truck send the clowns packing. "Killer Klowns" was released in 1988 and is hailed as one of the worst must see movies ever made.
Roddy Piper of World Wrestling Federation fame plays a homeless construction worker named Nada who discovers special glasses that can detect who's a space alien invader and who's not. Nada scores his find in a mysterious church. The device also uncovers subliminal messages that control the masses, such as dollar bills that really say "this is your god." With the help of a local homeless man and a woman named Holly, Nada discovers the secret television transmitter that disguises the aliens as humans. This is when the humans realize they've been doing hanky panky and other actions with extraterrestrials. Some even received traffic tickets from them.
"Invaders from Mars"
This movie, directed by William Cameron Menzies in 1953, was so cool that people did a remake of it in 1986. A giant head with tentacles leads a legion of Martians who take over human bodies. A young kid named David convinces a female doctor that this is happening, citing strange injection marks on people's necks. The doctor joins the fight to save humanity. 1953 is the height of the era of Senator Joe McCarthy, the man who saw communists lurking behind every corner. There's wide speculation that this was an allegorical film about the McCarthy era.
"Plan 9 from Outer Space"
If you want to see zombies, aliens, and vampires all in one flick, this is your choice. A group of aliens on Earth have good intentions-to prevent those stupid humans from inventing a solar powered bomb that can blow up the universe. The way to defeat the plan is to resurrect dead people as zombies and vampires and create a small army to foil the stupidity. In 1980, director Edward D. Wood Jr. won the Golden Turkey Award as the worst director ever. This is the only factor that made this 1959 movie popular. With these credentials, it must be worth watching.
"Invasion of the Body Snatchers"
Just like "Invaders from Mars", this flick from 1956 was remade into an equally bad movie in 1978. Kevin McCarthy plays the apparently paranoid and institutionalized Dr. Miles Bennell. As usual, it turns out that his paranoid delusions are actually correct. A group of aliens steal humans and replicate them with alien pods, starting with the town of Santa Mira. The human replicas are devoid of emotion and all things that makes humans human. Another similarity this one has with "Invaders from Mars" is that it's also considered an allegory caused by the hysteria of the McCarthy era and the mass conformity that followed.
It's not only the movies from the 1950's that are hopelessly stupid. This film from 2006 features an alien plague that turns people into zombies and mutants. The cause is a parasitic worm that rides a meteorite which collides with Earth. A man named Grant Grant (Michael Rooker) gets infected by the worms and becomes a monster, a worm breeder, and a zombie kingpin. It's up to Grant's wife, Starla (Elizabeth Banks), and the local sheriff (Nathan Fillion) to save the Earth from imminent doom.