Perhaps you've heard of the new fad among Kids These Days, which is jumping into cold water. Goes by many names: the Polar Plunge, the Cold Water Challenge, the Frigid Folly, doesn't matter. It's simple: Kid goes into the water. Friend shoots a video of the event, because the point of doing anything these days is to do it for the camera, and then it's posted online, because otherwise it didn't happen.

It's for charity, supposedly. Perhaps the American Association for Halting Hypothermia Health Hazards, or AAHHH, which is the sound you make when you jump into cold water.

A few years ago it was the Cinnamon Challenge, where you'd eat a cup of cinnamon then expel a gust of brown spice and weep while your friends laughed at you, because you ate a cup of cinnamon, you idiot. Next year it will be the Gasoline Gargle or Meet the Tree, where you run as fast as you can into a sturdy oak and fall over, bleeding.

I have a sensible child, and do not worry that she would drink gasoline because the Internet said it was funny. But the Polar Plunge is different. It is every parent's nightmare: Kids are literally jumping off bridges because their friends are.

It's the most irritating question a parent can ask. You wouldn't jump off a bridge because your friends are, would you?

NO. Of course not.

But that's really not sufficient; you want them to think beyond the hypothetical cliché.

OK, well, what if the bridge was on fire, or Nazis were going to blow it up, or Godzilla was about to smite it, and your friends had perfectly good reasons for jumping. How about then?

I suppose.

But it wouldn't be just to be popular, right? Good. What if everyone was bungee jumping? That would be a situation where you were engaged in a group activity under professional observation, so go ahead and jump and conquer your fears. But I'm going to want to see a permission slip.

(Blank stare, wondering where this is going)

So, any of your friends planning on doing the Polar Plunge off a flaming bridge because they want to bungee away from Nazis and enormous mutant reptiles? It's my duty as a parent to ask these things.

(Blank look of utter incomprehension)

There followed brief discussion of jumping into the creek, which some kids were doing because it seemed OK. Kid thinks: I'll walk into the water where it's shallow, and walk out, no big deal. Parent's conception: You will slip on the mud, strike your head on a rock, be carried along by the current and shoot over Minnehaha Falls, end up in the Mississippi and be carried into the Gulf of Mexico.

Child imagines: laughing over the stupid YouTube video with a few friends. Parent imagines: having to fly to New Orleans to identify the body.

Kid says: So, can I do it?

Parent says: You want to break your mother's heart in a Louisiana morgue, you go right ahead.

Why is it popular? Because it's all about the dare. They say it's not, but that's the heart of it. If you are dared, you must comply, or you are chicken, and this stays with you the rest of your life:

"Well, Ms. Horgensted, your résumé is most impressive, and your multilingual aptitude is just the sort of thing our international branches are looking for. I'd say you were a natural fit for our French office, but we're looking for someone who can meet new challenges square in the face, and according to our NSA intercepts of your social media activity from 10 years ago, you declined to walk into cold water when taunted by a peer. I'm sorry, but we're looking for a leader. Someone who jumps off a bridge, and everyone else follows."

In a way, you have to envy kids. There's something raw, pure and simple about these social challenges. At least you know where you stand: You went in the water, or you didn't. You resisted the parent-petrifying peer pressure, or you gave in. No one opens an e-mail and discovers he's been dared by someone in the office who read the Corporate Branding Mission Statement Objective Achievement Strategy in its entirety and now you have to do it too — and post a YouTube video where you say "I found the part about maximizing disruptive core-target assumptions really inspirational!" without looking like you wanted to throw a rope over a rafter.

Anyway. According to my sources, the Cold Water Challenge, or whatever it's called, isn't really a thing anymore. Which means they've come to their senses.

Or they have something else in the works. Just be on the lookout for stories that cite a puzzling increase of kids admitted to emergency rooms with the pattern of tree bark on their forehead. "They smell like gasoline too," said one doctor. "That's the confusing part."