It’s a sighting that made many people sweat.

Panicked nudists at the Bernaqua waterpark in Bern have spotted a drone hovering above a sauna area more than once over the past few days, The Local reported, citing 20 Minuten.

“A customer told a lifeguard, who warned the security guards,” said Andrea Bauer, a spokeswoman for the company that owns the waterpark. “The people who visit that area are naked or wearing few clothes. Protecting their privacy is therefore all the more important.”

The park has womens-only and mixed sauna zones, both of which are nudist.

It is unclear whether the drone has a camera attached. Flying a drone over a crowd is illegal in Switzerland, The Local reports.

Click for more from The Local.