I plugged my iPhone in to charge yesterday, and when I went to get in bed later that night, I found the phone was SUPER HOTTT, almost too hot to touch without pain!
The case that the phone was in (silicon case) was all greasy as if it were about to melt. I pulled the iPhone from the charger and tried to turn it on, to which I received a white screen. I then turned the iPhone off. I quickly grabbed my IR thermometer to measure just how hot the iPhone was.

It took longer than anticipated for the battery to cool, as I think the battery in the phone was still holding a strong charge.
And now, my iPhone is completely dead. It won’t turn on, recharge or anything. Just my luck.
I talked with Apple earlier today (had to borrow my roommates phone, blah). They are sending me a “service” iPhone to use in the meantime, which should be here tomorrow, as well as a box to ship my broken phone back to Apple. I was told that it isn’t terribly uncommon to have this happen, especially if you are using a case on your iPhone, which I was. I should have some type of fix / replacement in 3-5 business days.