Write about something mysterious.
In the natural world there’s lots of very unexpected, seemingly mysterious things that happen. Caterpillars turning into moths and butterflies. Jellyfish, as a whole, but specifically the ones that are immortal. Seeds being underground yet knowing which way to send their shoots and roots. Hibernation. Monotremes. I say “seemingly” mysterious, because of course we can eventually come to understand more and more about each of these things as we study them. But nevertheless, each of these is just one tiny example of the cacophony of unregulated nature. It’s beyond our expectations, wild, and works just fine regardless of our intentions or knowledge.
Then we move into physics, where lots of mysteries abound; quantum mechanics and string theory, and such. Theories are great, because they give us a way to examine something we don’t really understand, without tying us down to one way of considering it. Because we fundamentally don’t know. Anything that has an uncertainty principle you know right away: it’s mysterious.
Here’s a person-made mystery that is delightful in the overall shape of it – when Agatha Christie, famous mystery novelist, when missing for 11 days. No one knows where she went, but there was a massive manhunt after her abandoned car was found. She resurfaced at a spa. Two years later she divorced her abusive husband and good riddance to bad rubbish. Of course, the actual details hold no delight – a woman who was gaslit by a cheating husband for years, who drove off into the night after kissing her sleeping seven-year-old daughter, and checked into a hotel under her husband’s mistress’s name is most likely suffering from crippling depression, not out for a lark. Yet the symmetry of being famous for writing mysteries then being at the center of a mystery, which remains unsolved to this day, is intriguing.
So there are some mysteries, have fun.