The sources explore the possible origins of the berserker trance, a state of blind rage experienced by legendary Viking warriors. While the traditional hypothesis points to the hallucinogenic mushroom Amanita muscaria as the cause, ethnobotanist Karsten Fatur argues that the plant henbane, Hyoscyamus niger, is a more likely culprit. Fatur cites the similarities between the known effects of henbane and the described characteristics of berserkergang, such as aggressive rage, pain insensitivity, and altered perception. He also emphasizes the prevalence of henbane in Scandinavia during the Viking era and the lack of evidence for the widespread use of Amanita muscaria in the region. However, Fatur acknowledges that this is speculative, and further research is needed to confirm or refute his hypothesis.