|"Is this all real? Or has this been happening inside my head?"
The topic of this article is of a real-life subject that has been mentioned "in-universe" in a canon source. The Harry Potter Wiki is written from the perspective that all information presented in canon is true (e.g., Hogwarts really exists), and, as such, details contained in this article may differ from real world facts.
The travelling freak show Circus Arcanus featured Nigelle le Narcissique, a purported member of the species Homo Amphibia, who was billed as "freakishly devour[ing]" her own tail while singing Gaelic folk songs.