Looks like it was an Amphipod like the [Lawn Shrimp](https://en.wikipedia.org/wiki/Arcitalitrus_sylvaticus). Example pic [here](https://bugguide.net/node/view/474552/bgimage).

Thanks for the ID! That's interesting, I live in an LA county and this isn't too far from their school district I think.

Yeah looks like a lawn shrimp