When Steve Hill recently visited Australia’s Uluru-Kata Tjuta National Park—home to the iconic geologic formation Uluru, or Ayers Rock—he spotted a beautiful rock specimen that he felt compelled to take home. But after pocketing the piece, he couldn’t help but notice that his luck had soured. On his trip home, his car was attacked by kangaroos. Then it broke down. And all of the photos from his trip mysteriously vanished from his phone.

Hill became convinced the rock was responsible.

He’s not the only one. Some believe that the rocks removed from Uluru are cursed. In fact, offending visitors mail in so many pilfered specimens that park rangers have a name for the pieces: “sorry rocks.” Usually, each shipment of sorry rocks comes with a heartfelt apology attached. “I want to return the rock to its rightful place and say goodbye to the bad luck!” one visitor from Hong Kong wrote.

While a handful of people insist that the stolen rocks brought them bad luck, the vast majority of offenders return the rocks simply out of guilt. The land around Uluru is sacred to the indigenous Anangu people, and stealing the rocks is akin to lifting an icon from a church. (It also carries a steep fine of more than $6000 USD if the perp is caught.) According to the rangers, at least one package of sorry rocks comes back home every day.