Teen Salt and Ice Challenge
.. Just saw this on facebook so I thought I'd look it up. I don't understand why people come up with challenges just to hurt themselves. The worst we ever did in school (besides the pressure to get drunk) was jump off the bridge into the canal full of water (well..for those of us who could swim which wasn't me) and go to the 'haunted' cemetery.
The Salt and Ice Challenge (from wikipedia)
The mixture of salt and ice lowers the freezing temperature of water, and causes an endothermic reaction which can greatly reduce the temperature of the mixture.  This can quickly cause second and third-degree injuries similar to frostbite. Due to the numbing sensation of the cold and possible nerve damage during the stunt, participants are often unaware of the extent of any injuries sustained during the challenge. Participants risk suffering frostbite-like symptoms and second or third-degree burns. Skin discoloration from the challenge may remain after the challenge has been completed or failed.