I got the exact same message now (a Google search led me here) on a brand new, stock/unrooted Nexus 5x. The phone just locked up while I was browsing Google Plus, then that message appeared after a brief message saying that my phone was corrupt. It may be related to the OTA update I got an hour or so before it happened, or maybe not. Since I can't connect it to my computer without a USB adapter (which I don't have), my only option was hard reboot (the buttons weren't responsive), and it's been in a kind of bootloop ever since (with the corrupt message popping up on each boot). Since I can't reach the factory reset menu, and don't have a USB cable yet (it's in the post), does that mean I'm screwed until I get a cable?
Or: I could try to reboot to recovery with a key combo, I guess?
EDIT: After the last bootloop, it shut itself down and nothing starts it back up. Guess the phone's toast and that no amount of USB adapter trial and error will help me? Glad I took a picture of the "DemiGod Crash Handler" screen, at least, so I can easily prove too Google I did nothing wrong.