Holy crap, my house’s electrical system is possessed! Or something.
I’m lying here on my bed, surfing harmlessly, munching some cold pizza, listening to a bit of music (‘early 90’s’ playlist, aaaah). All the sudden, I hear, very loudly: obnoxiousloudgratingvibratingnoiseBANGobnoxiousloudgratingvibratingnoise
Me: MASSIVE burst of adrenaline Holy expletive, what the expletive was that? Then I catch my breath and explore.
I’d had an extension cord resting up on my dresser. It had my hairdrier and cell phone charger plugged into it, so the whole (large) ‘sandwich’ of big-bulky-charger, extension cord, hair dryer plug was up on my dresser. It is now on the floor
The hair dryer has one of those ‘automatically shuts off if the voltage goes all screwy, to prevent you from setting your head on fire or something similarly stupid’* features. I figure that for some reason, said function was triggered, in a non-optimal way, causing the whole shebang to vibrate itself onto the floor.
Hmm…Methinks I’m not going to use that socket or cord until I can have someone check it out…
The GFCI (ground fault circuit interupt) outlets are not normally off (meaning disconnected or powered-down) and thus wouldn’t tend to turn something on. It’s like a circuit breaker. Sometimes, it might happen to disconnect or break the circuit but can’t really turn itself or something connected to it on. The switch on the hairdryer might somehow click itself on, though.
Was the GFCI tripped when you found the hairdryer (did you have to press a button to turn it on?)
Are the hair dryer and cell charger still working? How about the extension cord?
I’ve witnessed severe electrical overloads cause odd things like making wires shake in conduit in addition to various noises. My best guess without being able to see and smell things is that the extension cord had an internal short that wasn’t quite enough to trip the circuit breaker, and the short resolved itself (ie: the wiring burnt out) before the breaker knew anything was wrong.
This, by the way, is why “arc fault” breakers are now being required for bedroom circuits - they can sense sparks in addition to regular overloads.