Warped nostalgia in online fandoms.In recent years, the growing levels of toxic behavior in online fan communities has become increasingly concerning, as many acts of harassment have been committed over trivial matters surrounding entertainment franchises. The purpose of this research was to understand how and why these toxic attitudes are emerging. 'Warped Nostalgia' is a proposed mental state in which an individual's emotional attachment to a fictional entertainment franchise or intellectual property (IP) becomes toxic, and they start to venerate the franchise's past, while disparaging the present. The proposed four component parts of Warped Nostalgia are Fandom, Toxicity, Nostalgia, and Enmeshment. Using various social media platforms, primarily Reddit, 322 participants were recruited to take a mixed methods survey on Qualtrics. The results found mild instances of the kinds of behaviors associated with the four component parts of Warped Nostalgia. However, chi-square analyses of the subscales created for the four component parts of Warped Nostalgia indicated that most were related to each other on at a p < .05 level. By finding these statistically significant relationships in such a generalizable sample, support has been established for the theory of Warped Nostalgia. A new model of Warped Nostalgia was then proposed for future studies, one in which A High Toxicity Environment corrupts the benign concepts of Fandom Engagement and Nostalgia into Enmeshment and Warped Nostalgia. This demonstrates the ways in which information systems can influence the psychological health of their users, while also showcasing the interconnectivity of the disciplines of information science and psychology. (PsycInfo Database Record (c) 2022 APA, all rights reserved)