And I just found this link saying it's from the Minions app which I have on my phone for my kids.
https://productforums.google.com/forum/#!topic/nexus/cHRzbIXsRC4
I just did a search and they are all .unity3d files. From a Google search they seem to be a part of some game emulator or something. I guess they are safe?
I have a screenshot. The file names are just a bunch of letters/numbers/dashes. No clue where these are coming from and if I should be concerned.
-Wasinator