ABSTRACT Artificial intelligence (AI) has an increasing presence in scholarship, posing new challenges and opportunities for qualitative researchers. Generative AI, such as Chat-GPT, can supposedly produce humanlike responses, which has implications for online qualitative research, which relies on human participation. In this paper, we contribute to debates about AI as a research participant (‘AI-as-participant’) and the threat of imposter participation in qualitative research. We share our unexpected encounter with AI during our story completion study on mobile dating during the COVID-19 pandemic and discuss how we identified AI responses within our dataset. Central to our analysis was our theoretical grounding of feminist new materialism, which attuned us to the affective and discursive qualities of our participant data. Using our theoretical lens, in tandem with other strategies, we examined the affective forces that signalled stark differences between previous, human-generated data and that of the current study. Analysing the discursive construction of narratives further alerted us to the absence of humans within our data. We conclude that AI cannot sufficiently replicate affect or capture the richness of human experience that is central to qualitative research, and offer recommendations for future researchers to anticipate and check for AI as an unwelcome research participant.