IPhone 7+ CHARGER exploded while charging?

My friend borrowed my apple charger for her iPhone 7+, it was plugged into an exetintion cord, it was working fine, then she tried plugging in her head phones and they didn't work. She atttempted to restart her phone but, it didn't work. Her phone got stuck on the white screen for a very long time approximately 5minutes then her phone was barley working. It would exit her out of apps and presss random things and freeze up. It has continued this pattern since. It was at 100 and froze to 1. Please tell us what's wrong!

Sadly, we can't tell you exactly what is wrong.

You should probably take it to an Apple store.