First, it was the "gallon challenge" and the "cinnamon challenge."

Then some teenagers started playing the "bath-salt challenge."

They have dared each other to pour salt in their hands and hold ice till it burns, douse themselves in rubbing alcohol and set themselves ablaze, and throw boiling water on unsuspecting peers.

Now videos circulating on social media are showing kids biting into brightly colored liquid laundry detergent packets. Or cooking them in frying pans, then chewing them up before spewing the soap from their mouths.

Experts say the game, dubbed the "Tide pod challenge," is dangerous.

"A lot of people were just saying how stupid I was or how — why would I be willing to do that?" 19-year-old Marc Pagan, who said he was dared to do it, told CBS News this week. "No one should be putting anything like that in their mouths, you know?"

It's not certain how the fad got started.

The U.S. Consumer Product Safety Commission issued a warning to parents several years ago about the liquid laundry detergent packets. The agency said the capsules - which are colorful, squishy and smell good — are attractive to young children but contain "highly concentrated, toxic detergent" that can cause harm.

In 2015, the Onion published a satirical op-ed from the perspective of a toddler who wanted to eat them.

At some point, the pods became alluring to older children. Last year, College Humor published a video titled "Don't Eat the Laundry Pods. (Seriously. They're Poison.)." It showed a college student researching the dangers associated with exposure to the packets, then devouring them. He ended up on an ambulance stretcher.

One expert conceded that young children are inclined to explore but was surprised at the number of older children and teenagers who are putting the packets in their mouths.

Last year, U.S. poison control centers received reports of more than 10,500 children younger than 5 who were exposed to the capsules. The same year, nearly 220 teens were reportedly exposed, and about 25 percent of those cases were intentional, according to data from the American Association of Poison Control Centers.

So far in 2018, there have been 37 reported cases among teenagers — half of them intentional, according to the data.

"You're really taking a chance — and to what end?" Alfred Aleguas, managing director of the Florida Poison Information Center in Tampa, told The Washington Post on Friday. "It's pretty foolish behavior."

Children who have been exposed to the capsules have been hospitalized with vomiting, breathing difficulties and loss of consciousness. And the consequences may be much worse. Since 2012, eight fatalities have been reported among children 5 and younger, according to the American Association of Poison Control Centers.

As with nearly any substance, Aleguas said, "the dose makes the poison."

The laundry detergent packets pose two potential problems, he said. Children and teens can aspirate on the liquid by inhaling it into their lungs, or they can become ill by ingesting it — experiencing a change in blood pressure and heart rate, losing consciousness or having seizures.

And because many teens may not have had the need for a thorough physical exam, Aleguas said, some may not know they have underlying medical conditions, such as asthma, that could put them at a higher risk for complications.

Tide did not respond to requests for comment from The Post, but its parent company, Procter & Gamble, told the Fresno Bee that the pods are meant strictly for use in the wash.

"Our laundry pacs are a highly concentrated detergent meant to clean clothes, and they're used safely in millions of households every day," the company said in a statement. "They should be only used to clean clothes and kept up, closed and away from children.

"They should not be played with, whatever the circumstance is, even if it is meant as a joke."