It looks a bit similar to this?
What is this thing?
Let us help you identify that mysterious object you’ve found.
Currently in CHALLENGE mode: If you've got something obscure knocking about, post a picture, and let's see how we do. Please prefix such posts with "CHALLENGE:" so we know we've got a fighting chance.
I'm thinking it's this sort of thing but not specifically. It looks like you insert it into a hole to undo a clip, such as to access the detector you link or to pop open a box to replace the toilet paper in a restaurant toilet or anything where you want something to keep out the kids but don't need full lock security.
Specifically I haven't seen and haven't searched up anything quite like this, but it does have that vibe to it.
A very sturdy IUD.
Oh man did I read that title wrong, I had to do a double take
I think it's for fixing a tire.
Are you thinking tire lever for a bicycle?
Looks too thick fore that, but does look like a levering tool of some sort.
More like a tool for inserting a tire plug in an automobile tire, maybe, but it's not quite the right shape for that either. (Or at least, if it is that, it's a really cheap one because usually they're made of metal.)

tire plug? what are they doing with those pretzels. patch? stem? i am so confused. i need more pretzels
i am growing to hate ai. it's not bringing me enough pretzels
Yea, its not that, too thick/square, handle too small, etc. You'd never get a plug in with it (I've done thousands of them - tire's are really tough).
Looks like some kind of levering tool.
As an aside, check out the screw-type tire plugs available today. Way easier than the traditional plugs and work just as well.
Might be a landscaping stake
OP, is that metal or some sort of plastic? I can't tell for sure from the picture
Its plastic. It feels hard but shaves off easily with a knife, and the shavings melt.
I hope this isn't your approach to every object you can't identify...
"When cut, it did emit some red fluid, and the object moved and made a lot of noise - perhaps some sort of hydraulic mechanism? The shavings don't melt, so it's probably not plastic."
Bahaha - reading this and taking a drink - bad combo, almost out the nose.
My best guess is some sort of "pin" for holding some other components in place or in alignment. It has those fins along the side that are chamfered in both directions and that notch at the end...
I almost thought it was like a "key" for turning something but I don't think the handle is big enough and I don't think plastic would be strong enough
Maybe some sort of packaging?
Could be some weird packaging thing. I think I've seen something like this when I bought a pack of ratchet straps.