Phil Blumburtt: Lilly had the dolphins. Cousteau the whales. Goodall, gorillas. I had a duck. I could have been a contender.
When the Overlord is busy destroying the Diner, when he starts destroying stuff on the counter, you can see the small rods pop up that flip the saucers and glasses into the air. You can also see the compressed air they used, to aid with the effect.
The film is considered one of the biggest cinematic bombs in history. It had a budget of $37 million, but only took in $16 million domestically. George Lucas, who served as an executive producer, disowned the film shortly before its release.