EDIT: I believe I found the answer, it's something turned by this: https://ctatools.com/products/5065
Found some trash on the street that i'd like to take apart, but this screw is in my way.
It's like a hex bolt, but with 5 sides, and rounded (a bit like flower petals).
Here's another picture from the top:
I tried turning it with various tools (hard to get pliars in unfortunately), no success so far. The material is very soft, which doesn't help..
Hard to say without a scale reference, but if it's small, I very small might very will be a proprietary fastener for higher security applications. If it's a Tesla battery pack, then the epr 5-point torx is a good candidate. If it's an apple device then searching pentalobe might get you farther.
What on earth is it? Pics? Ruler next to it?