The incident took place just before a wedding ceremony in Upper Austria on Saturday, where part of the celebration traditionally involves the bride being welcomed loudly by a group of young bachelors.
In preparation, a group had filled the balloons with gas and fixed them to a fence in a lawn to detonate when the bride arrived.
The fun trick ended in disaster, however, when 18-year-old Andreas W. had to be rushed to hospital by air ambulance after two balloons he was carrying suddenly ignited somehow and exploded.
One theory is that the clothes he was wearing caused a friction with the balloon that created a spark.
He was taken to hospital in Salzburg suffering first and second degree burns to his upper torso and hands.
“According to information from the doctor treating him, he will have to stay there for the next few days,” said spokesperson for provincial police Petra Datscher, quoted in the Kurier.