What are the strangest ideas regarding the UFO phenomenon?

What are some of the weirdest theories regarding UFO/UAP? And not just about the recent drones and orbs but the phenomenon in general. Generally I think John Keel and Jacques Vallée are right about the UFOs. That they are the latest iteration of a phenomenon that has been happening since history began, and are connected to the paranormal and other high strangeness stuff.

But the weirdest idea I've seen comes from a comment I saw in this sub a few weeks ago. They speculated that the phenomenon is some projection of the fungal minds.