Last month, a millipede expert in Denmark received an email notifying him that one of his publications had been mentioned in a new manuscript on Preprints.org. But when the researcher, Henrik Enghoff, downloaded the paper, he learned that it cited his work for something off-topic.

Stranger still, the authors of the now-withdrawn preprint, a group of researchers in China and Africa, also referenced two papers by Enghoff that he knew he hadn’t written. It turned out they didn’t exist.