That would be interesting to see what would happen if it just charged itself. I've done that with USB power banks where they inevitably get drained. Tried it with a Mac (with MagSafe) where the MagSafe input was driven by one of the USB-C outputs. The computer was actually saying that it would be fully charged in a few hours, but by morning it was close to shutting down.
Looks like a NEMA 14-50. I suppose a Tesla Mobile Connector would max out at 32A, so it could handle that.
https://www.tesla.com/ownersmanual/cybertruck/en_us/GUID-DA020526-B42E-4C0E-AE1E-BB22072D48B6.html
I have seen a Mobile Connector using a 120V extension cord and sitting in someone's driveway. The box was just sitting next to the car, so if it started raining it would have made for a pretty bad day for the owner.
