Really scary, spewed black smoke, black carbon dust around, the stench is horrible!
Wow, looks like an airbag went off.
For now I'm not doing anymore overnight charging on my 4s. I don't want it to catch on fire while I'm sleeping. There's been way too many reports of fires recently.
Everything was smooth, the battery was very slightly soft and not even bloated.
After replacing the back case, i realised, it can't fit in smoothly, so i removed the back case to see whats wrong... and then the battery started to bloat up like in really slow mo then.. HISSED and POOOOF spewing dark smoke and the phone was very very hot! the table was burnt as well!
Apple says to wait for their engineers instruction. Still waiting.