Stream of Consciousness: Nothing is indestructible, but rocks come to mind, but we’re talking fiction, so what was that one thing from a fanfic I remember… I don’t remember, but I feel like I’ve read at least some things where Ah! Horcruxes. Horcruxes are (nearly) indestructible and my favorite tacks for HP fanfic authors to take is for magic to be an interface to sufficiently advanced technology (or just “true” magic) set up by people thousands of years ago, maybe tied to Atlantis. Not too old, though.
Also, things such as energy and matter are indestructible in a sense since they can be converted one to another and lose the difference in energies at two points which allows for the energy to be useful, but it’s still there, for a given definition of matter and energy…
Like a riddle? Maybe something to do with social structures that have been around not for decades, not for centuries, not for millennia, but across the animal kingdom including such creatures as crustaceans?
I may or may not (totally am) influenced by JBP in this.
Nah, I guess it’s too old a joke to be relevant. No one under 25 would know what it’s about, so much for a clue! Yet you didn’t do the very thing you asked me to do before. Anyway, it’s not important. Or I’ll tell you later if you want. Meanwhile, I think I’ve inadvertently got another clue about your book, let me search for a minute.