There was a cartoon I used to see in the early sixties, black and white, probably old even then, maybe 30's or 40's. It had some kind of discordant jazz music in the background, no speaking, and there were these creatures who were essentially an eyeball on top of a vertical metal pole, with a wheel at the bottom. These damn things were, I think, chasing something or someone inside a building. I think there might have been predatory vacuum cleaners in it too.
I would love to be able to identify this and view it again as an adult. It absolutely terrified me.
I'm almost 90% sure the movie you're remembering is "Fantastic Planet." It was about humans enslaved by a race of giants who kept them as domesticated pets and exterminated the "wild" ones. One of the pets escapes into the wild and educates the wild humans with a computer headset, leading them to rebel. The giants use a series of extermination gadgets against the tiny humans, including poison gas, vacuum devices, and crushing spheres, and there are several scenes of humans being overwhelmed and slaughtered en masse.
http://en.wikipedia.org/wiki/Fantastic_Planet
And never mind. It was made in the early 70s. *smacks self for not paying better attention*