Weebles is a trademark for several lines of children's toys originating in Hasbro's Playskool division on July 23, 1971. Shaped like eggs with a weight at the fat, or bottom end, they wobble when pushed, but never fall completely over, hence the name. Some Weebles were designed to look like humans.
The popular catchphrase, "Weebles wobble but they don't fall down", was used in advertising during their rise in popularity in the 1970s and during the relaunch in the 2000s. _Wikipedia