You know what I think the problem with this thread is?
Too many people putting the cart before the horse. A lot of focus on creating a scenario, and not nearly enough on creating a purpose for that scenario.
If I may make a suggestion: instead of focusing on the weird event, instead focus on what you want the weird event to accomplish, and then you can backfill in the event as needed.
For instance; do you want to tell a mystery story? An action/adventure? A travelogue? Sex farce?
Before you start talking about what series and what powers and what characters, start talking about genre and theme and mood. Decide what you want to say and then come up with a way to say it.
SIs are great for this kind of thing. Because they can be about what you like. Explicitly.
When I sat down to write Hybrid Theory, I didn’t start with the scenario – I started with what I wanted to say. I wanted to say things about what I like. And what I like is fanfiction and crossovers. So to do a story about a fanfiction crossover, I did an SI. Because the story wasn’t about a crossover, it was about crossovers. It wasn’t just a story about a piece of fiction, it was a story about fictions and fanfictions.
I also ended up throwing a lot of other things I like into the story; philosophy and worldbuilding and stuff like that.
One of the last things I decided was what characters and settings to use. I had come up with themes and narratives and stuff like that first. My co-writer and I literally spent hours talking out which character most suited the role as SI host based on the theme we wanted to explore of failed wish-fulfillment.
So before dropping another idea consisting of “What if X in setting Y with twist Z?” perhaps instead start with “I want to tell a story about A; what X, Y and Z makes that most interesting?”
I’ll start!
I want to tell a story about how ridiculous power escalation in the fighting genre affects people psychologically; i.e., what is PTSD like in a universe where people can go from fighting rats in a basement to punching out God? What sort of setting and twist would be best to tell this kind of story?