The passenger, who has not been identified, was caught on CCTV video soiling the seats of a bus in Shanghai, in China, on the morning of 13th November.
The act went unnoticed until the driver, who was not named, discovered the nasty surprise.
Then, after reviewing surveillance footage, company staff spotted the culprit.
In the video, a young man, wearing a black jacket and a black face mask, is seen walking towards the empty back seats.
He crouched in the corner, where he appeared to pull down his trousers, and continued squatting for about half a minute.
Then, he got up, briefly looked behind him and re-adjusted his pants.
He then moved two seats further up on the opposite side of the bus and remained there until the bus reached the next stop.
He sat uncomfortably for a few minutes until he hurriedly got up and left.
The company, Yanggao Bus, said cleaners had promptly removed the faeces and the bus continued operating as normal.
Staff expressed shock at the incident as they said the young man had been riding in the bus for nearly an hour and could have gotten off at any of the nine stops that they passed.
Instead, he bafflingly decided to relieve himself on the spot.
The company added that they decided against pressing charges.
However, they urged all passengers that if they find themselves in some kind of emergency, they should alert the bus driver.