Bulging indicates it is damaged. So it is a DDR battery. Watch the video till the end. DDR batterys should not be transported or stored with other batteries. Home Depot Lowe’s and Staples apparently all have containers for regular recycled batteries but not DDR batteries
Lawn darts. Better’n tannerite.
That I’d like to see
Like I said, I did some research, and I am NOT going to do that.
"Do not put/store the battery in water."
https://www.ifixit.com/Wiki/What_to_do_with_a_swollen_battery
...
I looked online for instructions on exactly how much salt to add to the water, and I couldn't find one website (reputable looking or not) that recommended putting the battery in any type of water. 
...
So, Oli, if you have a source, please provide a link.
I think I'll order a fireproof & explosion proof LiPo bag to transport the battery.
Same thing happened to the battery in an iPhone 6 I had.
Took it to an Apple shop to have the battery replaced.
They flatly refused to even handle the phone, said it was forbidden by Apple to handle it doing a swap. Apparently really dangerous.
So YOU had to solve a problem that occurred with one of THEIR products?
And you were forced to fix this problem on your own?
On such a moment I wish I live in the USA and sue their pants off.
Take a look at this LINK
The links mentions a cracked screen, which is not uncommon with a bulging battery.
I don’t know your “situation”, but where I live I can go up and down a dozen times to the recycling facility before the explosion proof bag I order arrives at my doorstep.
Yep, but I'm in no hurry.
In this case, I'd rather be safe than quick.
(The potentially dangerous battery isn't going anywhere.) 
To be fair:
They did take care of the phone and sent it to destruction.
They destroyed the phone?
Couldn't they just remove the battery and leave the phone alone?
According to Apples instructions, they were not allowed to do that.
They did offer me to just take it back with me.
But I was just glad to get rid of it.
(Opening up an iPhone does put stress on the phone and battery, and I wasn’t that interested in taking the risk myself.)
Okay, I didn't know that. 
I have an inexpensive, but nice for the price, android phone, and removing the battery is no big deal for my phone.
iPhones are sealed units glued together, so opening them up normally includes both force and heat.
Not something for the faint of heart close to a dodgy battery…
Have you been IN some recycling collection stations? Often big bins, overflowing with batteries that people make no effort to prep in any way for safety. At least they are usually steel.
Search, battery recycling fires. Images or in general or news.
Risk isn’t zero but generally I think it’s overhyped for these. We get bunches of them at work, laptops and phones and other one-off devices. I clip the leads if it has them and/or tape over the contacts to prevent shorts, keep ’em in a small cardboard box until it’s convenient to drop them off. Lowe’s and Home Depot in my area have both stopped accepting recycling of any kind, but if you have a Batteries Plus or Best Buy, they’ll take them. Some Office Depot and Staples stores do as well. It’s a real hassle for us to take them to a municipal station here (being a business vs. residential customers).
Of course things not to do: poke, bend, pry, and drop. Not a fan of the submersion idea either.
The casings for these cells are way tough. If you’ve ever tried to tear one open, it’s not easy. They can handle pretty amazing amounts of pressure/bulging before rupturing. I wouldn’t worry about transporting it in the car but if it’s too concerning until then, just leave it outside on the concrete or a rock or something, in a metal can if you like.
For pouch/cased cells like this I will usually put them in a ziploc (individually) just as additional protection against shorts or pokes, and label the bag li-ion or li-po, etc, just in case that matters to someone as they sort the containers.
I’ve discharged a few 18650’s and a couple lithium poly cell phone batteries in “salt water”. They were completely dead by morning, didn’t explode, didn’t catch fire, they simply discharged over night.
This only goes for lithium ion batteries, which includes lithium polymer. Never put a lithium primary (like a cr123) in water. Lithium ion cells don’t contain lithium metal and the way to extinguish a lithium ion battery fire is with water. Lithium metal batteries on the other hand, create hydrogen when submerged in water. Trying to put out a lithium metal battery fire with water will make the fire worse with burning hydrogen. Reaction of Lithium and Water - YouTube
It’s controlled obsolescence. If you can keep replacing the battery in your phone , you are much less likely to ever replace the phone. Not a good situation if you are Apple or Samsung.
Biggest part of that was not obsolescence conspiracy but rather shrinking the physical size (until screens grew bigger and bigger…). Now we can have 7mm-8mm thick phones with larger capacity batteries to boot compared to a) the early days, and b) any phone with a removable battery and a now-standard hardware/feature set.
I do miss removable batteries, though.