Actually that does have a confusing name: Weakly Interacting Massive Particles. WIMPs. Yes, really.
It’s a common misconception that Dark Matter = WIMPs because it’s the leading theory right now. Dark Matter really just means “whatever happens to be the cause of certain cosmological measurement discrepancies” even if that cause isn’t in any way “matter” at all. It’s a very misleading name.
Accepting that the reality of a story is as described. Magic is real? Sure. FTL? Sure. The colour red makes you fart? Yeah why not? For the sake of the story, I Believe.
BUT the term often gets hijacked by rabid fans trying to justify plot holes, self-contradictions, and nonsensical gobilygook. Suspension of disbelief doesn’t mean I should also suspend all semblance of reason, unless of course there’s a clearly established in-universe justification for doing so.
If you put the die type along the top row (just the numbers, no d) and this in A2 it should do what you want.
=RANDBETWEEN(1,A$1)
You can copy the cell without editing the formula and fill as much of the sheet as you want. Press F9 to reroll.
If you prefer a percentile die with zero, you can change it to
=RANDBETWEEN(0,9)*10
Or just combine the 2 dice as a single d100
I think the idea is to build a habit of checking, so you don’t even need to have that “hold on, am I dreaming?” moment. You just habitually do that thing you always do, and then “oh it seems I’m dreaming. I didn’t notice”