Social media sites have been flooded by videos of people trying, and mostly failing, to climb the crates.
An AFP report explains that most of the videos end with painful fall onto the collapsing crates, or the ground, as onlookers film on their phones in what some dubbed an event in the "Hood Olympics".
In a report, Dr Chad Cannon, an emergency room doctor at the University of Kansas Health System said, "You're at risk for... hitting your head and getting a head bleed. If you land on the milk crate, you will break your back and be paralyzed."
Meanwhile, Baltimore City Health pointed out that hospitals are already under strain from the pandemic. "With COVID-19 hospitalizations rising around the country, please check with your local hospital to see if they have a bed available for you, before attempting the #milkcratechallenge," the official account tweeted.
The hashtag on TikTok returned no results, it was readily searchable on Twitter and Instagram. While the popular short video app has been banned in India since June 2020, the number of users on other social media sites adds up to millions.
"This phrase may be associated with behaviour or content that violates our guidelines. Promoting a safe and positive experience is TikTok's top priority," the search result page said.
"Several videos and photographs of some appalling injuries, were reminiscent of an earlier internet sensation that had doctors tearing their hair out," the AFP report said.
The 2018 Tide Pod Challenge saw young people biting into liquid laundry detergent packets, the report further added.
In 2020, the skull-breaker challenge had gone viral on the internet. In this dangerous act, which involves three people standing side by side, the two people on the side count till three and jump. When they land, the middle person jumps. When the person in the middle is in the air, the other two kick his/her feet, ensuring a hard fall that can lead to head injuries.