I put getting nailed on a broken neutral or a bad tap on the transformer. If you have an underground service I would check the meter pan first. But I would call an electrician and unplug everything. Depending on what it is at any time it could get worse and send 220 through everything. This would FRY most everything that was plugged in.
Hmm I’ve had 480, 440, 277, 240, 120, 48, 24, and 12. The bad ones were the DC.