Phone gone completely black and is super hot

My battery was on 35% last night. I plugged it in to my charger before I went to bed and when I woke up it was super hot. It was a black screen and wouldn't turn on. My brother has extra batteries so I decided to try one out and I put it in and charged my phone again. It turned on but was at 0% but everything was working fine when it did turn on. It then shut off and has been black ever since and is still hot to the touch.