The Green Slime (1968).

The Scoop:
Flora, a “class two asteroid” suddenly takes a left turn starts hurtling toward a collision course with Earth. The only man qualified to stop this menace and save the world is studly rocket jock Jack Rankin (Robert Horton), who must team up with arch-nemesis Capt. Elliott (Richard Jaeckel) to destroy the killer rock. They’re successful, but they find out on the way home that they’ve mistakenly picked up an alien slime that spawns silly tentacle creatures with a taste for human flesh. Meanwhile, in between rousing bouts of square-jawed heroism, Rankin and Elliott fight over sexy doctor Lisa Benson (Luciana Paluzzi).

So basically, this starts out as “Armageddon” and then turns into “Alien.”

This Japanese production is filled with the cheap effects and clunky performances you’d expect from your favorite Godzilla movie, but with a cast of American and Italian actors. It’s completely laugh-worthy, of course, but the best thing about it is the swinging title by Richard Delvy, quite possibly the best theme song of any movie ever.

Best Bit:
Besides the theme song? It's the groovy welcome back party. It's too swingin' for Earth, so they had to hold it on a space station.

Side Note:
All the extras are American military personnel who were based in Japan at the time.

Companion Viewing:
"The Wild, Wild Planet" (1965).

Links:
IMDb.
BadMovies.org.
Monster Island News.

Take a Look:
The trailer:


The theme song!