Nikon disqualified the first-place video in its 2026 Small World in Motion competition after a review found it violated generative AI rules. Scientists had questioned structures and cilia appearing or disappearing unnaturally. Entrant Ning Xu said AI was limited to post-processing and did not generate the motion itself. Nguyen Nam Nhat, whose video depicts a roundworm and a single-celled organism, became the new winner. Nikon expressly limited its decision to the video’s eligibility, not the entrant’s professional reputation, scientific contributions or intent.