Thankfully, it wasn't being used as a "lap top" at the time (imagine the lawsuit!).

I've heard of cell phones combusting. As they pack more and more gadgetry into smaller spaces it can casue serious heat retention issues.

My cellphone? A phone and nothing else, it's already a pretty uncool older model (5 years old, omfg)and I stedfast refuse to upgrade to newer phones while the old one works fine. Not like it is a computer or anything.

Does Japan use 220 volt?

Japan actually uses 100 volts, unlike anywhere else. Weither or not that is creepy I leave to other people to decide