What you are witnessing can be called some version of the invisible dragon argument. Brendon does this REGULARLY, it's so funny to watch.

"The Dragon in My Garage" is a chapter in Carl Sagan's The Demon-Haunted World, which presents an analogy where the existence of God is equated with a hypothetical insistence that there is a dragon living in someone's garage. This is similar to Russell's Teapot in the way it forms an apt analogy for the concepts of the burden of proof and falsifiability. The main thrust of how Sagan develops the garage-dwelling dragon example is that the proponent employs increasingly ad hoc reasoning to describe their belief in the face of further questions. Eventually, the goalposts are moved in such a way as to render the initial assertion practically unfalsifiable. In a more general sense, this part may be done during the initial definition of the belief, or as when replying to critical examination of the belief in question.

"A fire-breathing dragon lives in my garage"

Suppose (I'm following a group therapy approach by the psychologist Richard Franklin[4]) I seriously make such an assertion to you. Surely you'd want to check it out, see for yourself. There have been innumerable stories of dragons over the centuries, but no real evidence. What an opportunity!

"Show me," you say. I lead you to my garage. You look inside and see a ladder, empty paint cans, an old tricycle--but no dragon.

"Where's the dragon?" you ask.

"Oh, she's right here," I reply, waving vaguely. "I neglected to mention that she's an invisible dragon."

You propose spreading flour on the floor of the garage to capture the dragon's footprints.

"Good idea," I say, "but this dragon floats in the air."

Then you'll use an infrared sensor to detect the invisible fire.

"Good idea, but the invisible fire is also heatless."

You'll spray-paint the dragon and make her visible.

"Good idea, but she's an incorporeal dragon and the paint won't stick."

And so on. I counter every physical test you propose with a special explanation of why it won't work.

Now, what's the difference between an invisible, incorporeal, floating dragon who spits heatless fire and no dragon at all? If there's no way to disprove my contention, no conceivable experiment that would count against it, what does it mean to say that my dragon exists? Your inability to invalidate my hypothesis is not at all the same thing as proving it true. Claims that cannot be tested, assertions immune to disproof are veridically worthless, whatever value they may have in inspiring us or in exciting our sense of wonder. What I'm asking you to do comes down to believing, in the absence of evidence, on my say-so.