This is the moment a burly Russian man administers a crunching knee to the head of a passenger who reportedly refused to stop vaping on the bus.
The incident was filmed on a bus in the city of Novosibirsk in the southern Russian Siberia region of the same name.
Local media said the passenger was smoking an e-cigarette on the bus and refused to stop when several passengers complained.
One man jumped to his feet and reportedly threw the e-cigarette out of the window of the moving bus, prompting a violent encounter.
In the footage, the burly man apparently shoves the vaper into his seat before grabbing his T-shirt.
The smoker throws a right hook at the stocky passenger but misses and unbalances himself.
As a result, the man pushes his head down, pulls his hoodie over his head, and delivers a knee to his face with a sickening thud.
The passenger then leaves the bus as the vaper gets to his feet and apparently wants to continue the brawl.
The transport company and regional directorate for the Ministry of Internal Affairs said no further action is currently being taken as no one has reported the incident to the police yet.