Stop us if you've heard this one before -- a cow walks into a barbershop ... and, while a ton of shocked patrons scram, the bovine beauty's ready for a fade!

Not exactly a great punchline ... but it is true, and it's all caught on "udderly" shocking video!

The wild moment went down earlier this week in Nanyang, a city in China's Henan Province ... when a cow ran in through the front door and caused quite a bit of mayhem, clearing the place out, and bumping a large piece of furniture holding the camera in the back capturing the scene.

Everyone heads for the door ... including customers with salon capes still wrapped around their necks, and stylists still holding scissors.

It's not exactly a bull in a China shop situation ... 'cause the creature keeps relatively calm after her first aggressive charge -- and, even seems fascinated by her own image -- stopping by the mirror and taking a keen interest in her reflection. The cow calms down and stands silently next to the counter, patiently waiting to receive the next clean cut.

According to local media reports, the cow's owner says his creature got nervous while being loaded into a truck, and made for the shop. The owner reportedly had to pay a fine of about 1,000 Chinese Yuan -- $137 USD.

The barbershop is reportedly open for business again ... but, we doubt they're getting into the animal-grooming game anytime soon.