SMC almost exploded
 

So it is swollen? That can happen if it loses too much charge in storage as well. My first and most expensive battery sadly suffered that fate last spring. You could check the voltage with a charger or something if you're curious, but if it is indeed badly swollen the best practise is to fully discharge it and then dispose of it.

salt water bath does nothing to make a lipo safe only thing a salt water bath does is dissolve the battery terminals. discharge with a brake light then recycle it best option .

Salt water is slightly conductive, it'll slowly discharge the battery.

keep it in the back yard or whatever in the mean time. I would not let that thing in my house!

I store all of the lipos in my house and garage in metal, locking ammo cans. That includes the ones for my rc cars, power tools, and yard tools. Can't be too safe.

Glad it didn't explode on you. If you have a bb gun and a fire pit, you could always have some fun with them.

I "played" with an old lipo and my pneumatic framing nailer. Can definitely be fun.

I had a venom pack do this shortly after purchase. It was under warranty at the time, so when I contacted venom they had me give the bad battery a salt water bath for about a week. I had to take pictures of the process, send them in, and was taken care of quickly after that. Salt water will allow the pack to safely discharge to nothing and then can be thrown right in the garbage.

Ouch, that's indeed a very dead battery. I had one swell a lot when it was (luckily) near empty and I accidentally shorted it - moved a metal object on top of it so that it touched both bare wires as the battery didn't have a connector at the time. But it was a softcase so it didn't look as dramatic as that.

Seen this happen to a guy who charged his batteries in a nice cool house, put all his charged batteries in the trunk of his car and after a couple hour drive to his favorite bashing spot, all his brand new packs in the trunk were swollen up like this because of the extreme change in temps... heat will increase the voltage of a LiPo which will cause them to swell.