Screen went black, took it apart and battery started to smoke.

I was using my phone and everything was working fine. I then went back to use my phone about an hour later and the screen looked like it was trying to start up, like it was first booting up but without the apple logo. I then attempted to take it apart to take the battery out however when I did start to lift the battery out it began to smoke. The phone was on because we could not turn it off. When it began to smoke I put the phone back together and tried to charge it, It vibrated as if it was taking a charge but the phone didn't turn on, I left it there for about an hour and when I came back it was very hot and I unplugged it. Any suggestions? Is my phone toast or would a new battery do the trick?