Had an idea for an Owl House/Ben 10 AU
We start a few months after Ben and Rook witness the creation of the universe, in Gravesfield Connecticut, where a ten-year-old Luz Noceda finds what seems to be an Omnitrix replica with a cracked, greyed-out dial half-buried in the woods. Then, impulsive child that she is, she puts it on, at which point she discovers that it is both very much real and not entirely inactive because it immediately grafts itself onto her.
The relevant authorities get involved pretty quickly and it turns out that while the damage is minimal enough that the self-repair system should’ve fixed it in a couple hours, there’s an excessively powerful and complicated stasis spell on the device, one centered around what looks like a crescent moon sticker on the back. A spell so powerful and complicated that nobody can actually figure out how to safely get rid of it. Even Azmuth can’t get it off of her because it’s not active enough to accept codes.
So Luz is just stuck with a completely useless version of one of the most powerful objects in the universe attached to her arm. As if she wasn’t weird enough…
Then four years, several false leads, and a poorly-thought-out book report later, she stumbles into the Boiling Isles and hugs the stuffing out of the last living Titan, and with the spell broken the Omnitrix finishes repairing itself around when Wrath chops Eda’s head off.
(As I’m sure you’ve gathered Luz’s Omnitrix previously belonged to the Archivists. Specifically, they retrieved it from a dead universe since they needed at least one for the Archives but all the ones with active wielders are off-limits due to being too important to Reality’s continued existence. It’s damaged and inactive because that’s just what it was like when they found it. How it ended up in Gravesfield is Spoilers.
It looks like the original series Omnitrix, except that when it’s damaged all the green bits are grey and after it’s repaired it gets Stringbean’s color scheme for some reason.)