A twelve year old boy from Pittsburgh suffered burns to his back after doing the salt and ice challenge Friday evening.
The salt and ice challenge is where a person first puts salt in his hand. Then, he takes an ice cube and places it on top of the salt in his hand.
From a chemical perspective, the reaction between the salt and the water causes for heat to be released. The heat can cause blisters and burns.
In this case in Pittsburgh, they made a salt cross on the child's back. Then, ice was placed on top of the salt. Finally, his "friends" pushed down on his back. The child was rushed to the hospital as he seared a cross into his back.
Source: Pittsburgh Gazette