It is true what internet writes: LiPo batteries can be dangerous. This is how ended one of my buddy’s batteries during indoor FPV session. Small crash, 2 seconds later cloud of white smoke and flames.
Reason was pretty simple. During crash battery got loose and still spinning propeller has cut 2 cells. Good thing, besides dead LiPo, no damage. We were lucky enough to get that thing outside before it damaged quadcopter or got anything else on fire.