Two men, known only as Giresh and Pashupati, began fighting at a festival in India while working together before the brawl turned into a gruesome nightmare.
The pair had reportedly been involved in a three-year-long feud which ended with Pashupati, 24, allegedly chopping off 36-year-old Giresh's head.
Locals said the horrific incident, which occurred in an "isolated spot" in Mandya city, India, was linked to Giresh's romantic feelings towards the younger man's mother.
Onlookers claim he drove 20km on his bike to Mandya city carrying it by the hair - and walked into a police station.
Pashupati has been arrested on suspicion of murder.
Superintendent of Police Shivaprakash Devaraj, said: "We are investigating the incident, but the accused and the victim were good friends.
"Pashupathi informed the police officials that Girish spoke ill of his mother, which triggered a fight between the two."
The incident happened on September 30.
Police said it was the third beheading incident in the state in a week, and officers fear the publicity they generated could be inspiring copycat crimes.