Children have been told not to hide in department stores as part of an online craze, with police warning the consequences could be "catastrophic".
The "24 Hour Challenge" encourages people to hide and build forts in large shops and warehouses overnight, before sneaking out the next morning.
In one case, Abid Mirza from Sheffield said he went through a "very rough time" when his 11-year-old son allegedly spent the night in an Ikea.
Detective Inspector Anna Sedgwick from South Yorkshire Police said the risk and harm that could be caused by taking part in the challenge are "by no means humorous and could be catastrophic".
DI Sedgwick added: "Warehouses and shopping departments contain large quantities of heavy stock and items that could easily fall and crush someone if they are moved incorrectly, or used to build makeshift forts.
"As well as the safety risk, children often do this without the knowledge of their parents, which could lead to large-scale searches or even cause them to be reported as missing.
"This not only causes fear and worry for parents, friends, family and the local community but can also be a waste of valuable police time, which may be needed to respond to a life or death situation."
She said the force is working with schools to raise awareness of the craze and appealed to parents to speak to their children about it.
"A few words of advice could save your youngsters life," DI Sedgwick added.
Ikea warned teenagers in 2016 to stop sneaking into its stores for illegal sleepovers following a spate of incidents in Britain, the US, Canada, Belgium, the Netherlands, Sweden, Japan, Australia and Poland.
The Swedish firm said trespassers often hid in wardrobes at closing time and warned anyone attempting the stunt that they could face arrest.
Two Belgian YouTubers have been credited with starting the craze with their video of a 12-hour stay in a store, which has been viewed more than two million times.
The pair filmed themselves jumping on beds and reading bedtime stories before hiding in a wardrobe and leaving undetected after the store reopened.