Didn't know enough at the time to be able to diagnose what had happened, and I had just started playing with containers so doubtlessly I fucked up somewhere. But it seems so utterly weird that (a) it could happen and (b) that a newbie could easily accidentally stumble on something that'd cause everything to go to shit.

I just ran lxc-destroy on what I thought was a container, started running into lots of issues in Chrome running on host so I closed out Chrome to try to restart it, at which point its binary couldn't be found so I blindly restarted hoping it'd fix it. And... there was nothing.