It may seem like a harmless prank - breathing in helium to make your voice sound like a high-pitched cartoon character.
Selena Gomez recently tried it with Jimmy Fallon on his show. Even a grandmother on YouTube did the stunt.
But when 14-year-old Ashley Long from Medford, Oregon, inhaled helium at a party, she was dead within seconds.
"They told her that it's not going to hurt you, it's just going to make you laugh. You're going to sound like a chipmunk," said Long's devastated mother, Lori.
Long inhaled helium directly from a tank - the kind that is used to blow-up party baloons.
The pressurized helium literally made Long's lungs explode.
The autopsy report says Long's death was caused by "Traumatic embolism...due to inhalation of helium gas."
"It's hard to accept but after she took the hit in, it completely went down to her lungs, and exploded her lung and after it did that it exploded her brain," said her father Justin.
The helium tank for that fateful party was reportedly purchased at a Toys 'R Us store. INISDE EDITION has learned that purchasing the tank can be simple childs play.
Long's own 8-year-old cousin was so upset about the death, she went undercover to show how easy it is to buy a helium gas canister with no questions asked. All perfectly legal.
Now Long's broken-hearted parents are trying to give the shocking tragedy some meaning by warning parents and teenagers about the dangers of the common party trick.
Lori said, "I was supposed to have a whole lifetime of things to do with her. And I feel like I've been robbed. My most precious thing has been taken from me and there's no way to get it back."