A 34-year-old man in western Germany has died after being crushed by a mechanical digger while taking part in a Facebook craze called the cold water challenge.
The digger's bucket had reportedly been filled with 2,000 litres of water and was supposed to be poured over the men.
Isselburg deputy mayor Klaus Dieter Spaan told German newspaper Bild: "It was harmless fun. Someone would dump a bucket of water from the town hall over them.
"But now everything is different. We all regret this tragic accident.
"The danger is that the groups want to out do each other and always take greater risks."
The cold water challenge is much like neknominate in that it is a dare passed on between friends across Facebook.
It has progressed from people pouring freezing water over themselves to jumping into cold lakes.
Even frozen ones.
Some groups of friends and colleagues have also started incorporating heavy machinery to help pour huge amounts of water over them.
A 19-year-old man died in France in June while taking part in the challenge.
He reportedly rode his bicycle into a river in western Brittany and drowned after he tied the bike to his leg.
According to Sky News, police in France have now warned people not to be "influenced by a stupid phenomenon of the moment".