What are the seapods that would be in the sky?

I was listening to an interview by Gordon Cooper (Mercury and Gemini astronaut), and he was talking about his experiences with UFOs that he had in the past when he was a test pilot. He said when he asked the government to open up a probe to the UFO phenomenon that he and countless other pilots had reported seeing, the government stated that they believed what the pilots were seeing were seapods. I've been all over the internet, and cannot find anything that tells me what a seapod is or how it could get into the sky and mimic a UFO. Can anyone explain this to me or lead me to a website that would explain this further?