Going back a couple of episodes, it just occurred to me where I heard the “Ventura, ventura, space people” chant before:

In an episode of 80s Urusei Yatsura:

www.youtube.com/watch?v=3kbmZdeuBnU

This is from the a dubbed version, but it’s the same thing in the original Japanese.

According to a reddit post, it came from a Japanese UFO society …kookscience.com/…/Cosmic_Brotherhood_Association…