Hum, put it reversed in a flashlight without Reverse Polarity Protection and measure the heat 
Maybe with some matches inside and flamable liquid too 
That would be a Hell Of A Shot — a 18650 at 1000 yds — Please video
He’s joking, the best marksman would spend all day trying to hit that at 1000yards with consumer grade guns and ammo. And still never hit it.
you think
I remember a few years back word going around the internet that Apple had released an iOS update that allowed the latest model of iPhone to be recharged in a microwave…
Find some Ukrainian guys with swim-goggles (safety equipment) and a hammer and/or axe.
Ooh, ooh. 12ga shotgun shell (~18mm), cut down to remove the shot but leave the wadding, drop the 18650 in there musket-style, and blast it into a brick wall.
18650… that’s a little loose for a 12 gauge and a bit tight for a 16 gauge… but I bet it would fit nicely in a in a high-brass 3” 12g birdshot shot cup.
Just Saying…… 
Or, maybe you have a pair of large jaw vice grips or channel locks that need heat treated?
Hence “leave the wadding”. Let that do all the work. :laughing:
That shotgun idea could be impressive.
Or it’s possible the sidewalls of the battery will buckle due to the high acceleration involved, jamming the battery inside the barrel, likely damaging the barrel and potentially even creating a risk of overpressure.
I wouldn’t recommend it without taking significant precautions.
don’t use a full choke barrel 
Yea, that’s what I was thinking. I can’t guarantee my safety doing that, so that idea is out.
Okay, so back to the Ukrainian guys…
If the cell fits in the shotcup, and the barrel is not choked, it will be safe.
One word.
Tannerite
Well I see two possible outcomes, a screwed up gun and/or personal injury… or it fires like a normal projectile and is boring.
Yea, you probably shouldn’t be posting that word on the internet. 
Why is that? It’s perfectly legal, as far as the ATF is concerned.
@JoshK, since I’m the kind of person that likes to be friendly to my surroundings and the general environment, here’s what I would do:
1. Discharge the cell to 0V.
2. Go outside with a bucket of water.
3. Wear two pairs of medical gloves, and a full laboratory suit.
4. Open the 18650 by removing the top cap with a dremel.
5. Proceed with the disassembly of the cell, by first putting the steel casing in the water to clean it, and then doing the rest WITH GLOVES ON. DO NOT TOUCH YOUR FACE IN, and wear a respirator if possible.
Then I could use it for a custom flashlight body 
Yes, but make sure to put the casing in water so that the electrolyte(comprised of HF and other solvents) gets converted into a safer form.
So yeah, just don’t open the cell up without gloves.
Some things I discovered:
1. The cell casing and anode can easily be recycled. The casing can be melted, while the anode can be rather easily separated into graphite and copper. The cathode is another story.
2. There’s quite a bit of copper inside of a cell. With thousands of cells, this could actually get rather profitable if you were to actually recycle it.
3. If you could actually weld them shut, you could make conductive spacers.