The "salt and ice" challenge numbs skin to the point where kids may not realize they're in danger of second-degree burns.

Salt and Ice Challenge
Credit: Issy Khan YouTube/Instagram

Every month or so it seems like there's a new viral online "challenge" that my kids and their friends are into—some of them more harmful than others.

For example, the beginning of the school year brought us the Mannequin Challenge, which basically required teens to do nothing more than freeze in place while the rap song "Black Beatles" played in the background.

But then a few weeks later it was followed up by the Backpack Challenge. "One kids stands in the middle of two lines of kids and everyone throws their full backpacks at him as he runs past," is how my 11-year-old son explained it at the time.

Really, guys?

Then last week, my kids my were obsessing over YouTube vids of the No Singing Challenge, in which participants have to listen to a bunch of popular hit songs while trying not to move to the music or sing along. Pretty innocuous, but still way harder than you think it would be!

Now, though, there's a dangerous challenge making a comeback. It's called the Salt and Ice Challenge, and it involves putting a bunch of salt and ice together on your skin. Why? Because the salt can bring the temperature of ice down to as low as 1.4 degrees Fahrenheit, with the effect on skin mimicking frostbite. And because the ice makes the skin numb, a lot of kids don't even realize they are doing any damage—but some participants have ended up in the hospital with second-degree burns!

I have a vague memory of doing the whole salt-and-ice thing back when I was in middle school. Only back then, we'd wash off our arms the second we felt the tiniest sting of pain. Now, thanks to social media, the challenge has reached Code Red status as kids compete to see who can stand the icy pain the longest, then post photos of their burns as proof.

"The rise of social media has contributed to increasing peer pressure among children," a spokesperson for the National Society for the Prevention of Cruelty to Children in the UK explained to Huff Post UK. "This 'craze' is another clear example of the risks."

The NSPCC then offered the following tips for kids being peer pressured into the challenge by friends:

1. Say no with confidence.

2. Try not to judge those who take part.

3. Spend time with friends who do say 'no.'

4. Suggest something else to do instead.

Hollee Actman Becker is a freelance writer, blogger, and mom of two who writes about parenting and pop culture. Check out her website for more, and then follow her on Instagram and Twitter.