Not exactly a horror story, but here it one. I decided to send proofs to a well-known academic publisher in order to report colleagues who had used findings from my lesser-known research papers (published in lower-profile journals) and my PhD thesis as their key conclusions. The Publisher started an investigation, but I was told that my colleagues would need to see the evidence first. The Publisher would not disclose my identity, I was certain that my "colleagues" would have figured it out. So, I made the decision to call them first and ask for clarification. They requested me to send them their text and works for which I was claiming authorship while acting as though they had no idea what I was talking about. After I sent the email, they called back, berated me, and threatened me with a lawsuit for defamation for using the words "Below is the text from the paper, which contains ideas taken from my publications.". They explicitly used the words "by all possible means". Then asked for apology. I did apologize and urge the Publisher to halt the investigation, but was this the proper course of action? Back then I was scared, but I am angry now. My sin is that my papers and Ph.D. results are not published in the big academic publishing companies (so they cannot find the plagiarism), except for one in Elsevier.