The only reason that didn't set the building on fire was that I was right next to the speaker when it burst into flames. My immediate reaction was to assume my SO playing a really unfortunate firecracker prank on me, but half a second later it was obvious it was the speaker's fault. Turns out batteries can make pretty flames and a lot of fairly unpleasant smoke. To this day, still can't believe how lucky I was to be right next to it with a pillow as it blew up.
The company was kind enough to send us their top of the line product for the incident, in exchange for the faulty unit (for them to study) and a written agreement to not take em to court.
Still pretty uncomfortable around charging devices with batteries to this day, but the reality is that it's unavoidable and there's no point in developing a phobia about it.