My working hypothesis, though, is that this is mostly funny because of the conjuction between the familiar and the unfamiliar. There is then a second layer of funniness to do with absurdity.

So, Chesterton's Fence is a bit of a meme (in the original sense) on HN now. I've seen it come up a few times, as something people consider obscure, but are eager to share, because it's interesting. I assumed that people would recognise it. The re-formulation as a piece of Kryptonian philosophy (Zal-Tar is the scientist guy from the 1984 Supergirl film) about something fantastical and over-the-top like an ancient evil trapped in a crystal, on the other hand, is unfamiliar. There's something about the superposition of the two that is funny.

However, that feeds immediately into absurdity, because my re-formulation is rubbish; it's entirely unconvincing, and fails to disguise the origin of the quote. But that makes it more funny, because now you think i'm an idiot. Except you know i'm not really an idiot (well, something like that), you recognise that i'm playing at being an idiot. That isn't a universal element of all comedy, but it's something i personally lean on a lot - if you can make a really obviously silly statement the right way, either deadpan or hyperbolic, it can be funny.

I'm reminded of "You've not experienced Shakespeare until you have read him in the original Klingon.":

https://www.youtube.com/watch?v=HsCVuO1yeJc

I don't know, this seems pretty obvious to me.