My beautiful Nexus 5X after being almost fried. :( A few days ago I go to my room where the phone is charging, connected with a good (+Benson Leung
approved) Belkin 6-Foot 2.0 USB-A to USB-C Charge Cable. And the whole thing burns
to the touch, remarkably the back side / battery. Surprisingly the phone was working, but not very much charged.
Maybe the problem was the cable being connected to power via one of those surge filters that have USB-A connectors, instead of a proper power adapter. (The phone couldn't charge in quick mode in that arrangement, but that was my night stand's charging station so I didn't care much for charging time.)
After removing the cable from phone, I had to discard it because it was severely damaged; part of the plastic from the USB-C end of the cable just melted inside the phone's socket, which didn't look good either. Even the battery cover and the case were damaged. I couldn't fit another cable in the socket because of the molten plastic inside it. So I reached for a SIM extraction tool, which has a very strong but thin pin that fits anywhere, and used it to scrape all plastic scum from the socket... and voilà, everything is perfect again! Even battery life seems completely normal, it's amazing. Only resale value went to hell, I'll have to keep the 5X as a backup device when I move to the next one.