The great stop-motion animation wizard Ray Harryhausen (1920-) is perhaps best known for his mythological fantasy films such as The Seventh Voyage of Sinbad (1958), Jason and the Argonauts (1963) and Clash of the Titans (1981; a remake will be released sometime this year).
(What is stop-motion animation? Click here to see.)
But Harryhausen, after working with the famed special effects maker Willis O' Brien (responsible for 1933's classic King Kong, among others) and then striking out on his own, first made a name for himself in the 1950s (after assisting O'Brien on 1953's classic The Beast from 20,000 Fathoms) on three low-budget, black and white, science fiction films. Those films, predating his work on Seventh Voyage, suffer somewhat from miscast actors, unfocused scripts and indifferent direction. But when Harryhausen's animated characters and spaceships take the screen, the audience is riveted. All three films make up the Ray Harryhausen Gift Set DVD collection (with a nice informative "collectable scrapbook" included), available here online from the library.
The three films in this set (I've included the trailers so you can appreciate Harryhausen's effects) are:
It Came From Beneath The Sea (1955): Due to radioactive fallout (boy, were we naive back then), a giant, six-armed (thanks to the low budget) octopus with a taste for people invades San Francisco and atomic submarine captain Kenneth Tobey (1951's classic The Thing) and scientists Faith Domergue and Donald Curtis try to figure out a way to destroy it. Tobey and Domergue give better performance-wise than what they got from the script and direction.
Earth Vs. The Flying Saucers (1956): A silly misunderstanding leads to war between the Earth (or at least the US military) and an invading army of alien spaceships, or "flying saucers". A weak cast headlined by All About Eve's Hugh Marlowe is blown off the screen when the saucers (which actually seem more life-like than the cast) arrive. Lots of famous American monuments get destroyed in some great effects-laden sequences during the climax. The saucer sequences had a big influence on director Tim Burton's 1996 Mars Attacks! film.
20 Million Miles To Earth (1957): Returning from an ill-fated trip to Venus, astronaut (and future Perry Mason regular) William Hopper (who's actually quite good) tries to track down the rapidly growing organism called the Ymir which is running amuck in the Italian coutryside.
The respective screenwriters (including George Worthington Yates, The Wolf Man's Curt Siodmak, and Christopher Knopf) and directors (Robert Gordon, Fred F. Sears and Nathan Juran; the latter would return for Seventh Voyage of Sinbad) don't really flesh out the events in the films or add any kind of fresh tone or style to the goings-on. They just provide the dramatic excuses for Harryhausen's effects work to make an entrance. Yet, they're still goofy fun, and once those stop-motion animated creatures show up, the audience won't care about any defects in the films' storylines and characterzations.