Probably for holding together some body panels

It was only connected by a screw through the bottom hole, and the larger bit was dangling down over the tire. Not a bracket, or holding anything together. The pokey bits are loose, and can spin in the mount

It's pretty obvious what it is, nobody even needs to write down what it is, much like a dodecahedron.

You can look it up if you know the model

2013 Lexus what?

My Dad is a mechanic and, whilst I am not, I've spent some time watching cars be disassembled, that looks to me like a plastics plug. So underneath your car is a whole heap of plastic lining that kinda seals off the underside, in parts, like mud flaps but for the wheel wells and front underside. Those plastic nubs on the end are plastic screws / plugs, to attach the plastic to the metal body, via a trim edge. That particular part looks like a bracket form of the plastic screw / plugs. Just check the plastic isn't lose or bowing down near the wheel well where you got it from. It would be almost impossible to see where it goes without getting it up on a hoist.

Banana for scale?

Where/how in the wheel well was it screwed in?

https://imgur.com/a/Utxov43

I hope that link works, Lemmy wouldn't let me post it here 🫩

Spokey-dokey?

That is an anchor for a child's car seat tether strap.

What's it made of? Any markings or numbers? Can you upload a few different angles?

Maybe part of an old mud flap installation?

To be clear it was screwed in when you found it and you removed the screw to remove it?

Could it be at some point in the past, the car was booted and when it was removed, this component was negligently left behind? Would explain it being only at one wheel, and a front one.

Might be some sort of motorcycle seat mounting bracket