We’re all used to cretins on the subway, but crustaceans?

Video and photos have been circulating on social media showing several live crabs taking up precious seat space during rush hour Monday on Line 1.

Kristina Hughes was on the subway at the time and posted a photo of the crabs on her Facebook page, along with a strange account of a passenger becoming enraged that the crabs scored sweet seats while she was left standing.

“Then a girl walked by, thinking there was a free seat, saw the crabs, let out a small shocked scream, and kept walking. About 30 seconds later she comes storming back,” she wrote on Facebook.

The woman, apparently fed up with the display of shellfish behaviour, began yelling at a man who appeared to be the owner of the crabs. “What is this s**t?!? What is this?!? Crabs on the seats? So no one can sit down?!?”

By all accounts, the crabs were breaching subway etiquette by putting their claws on the seat, but not everyone thinks they deserved what came next.

Hughes says the enraged woman swatted the crabs off the seats, launching one onto another stunned rider’s lap.

“That’s crab assault, man!” someone cried out. “She just assaulted the crabs!”

The TTC’s Brad Ross told CityNews he was aware of the incident and reminded riders to abide by the rules.

“Crabs are not permitted on seats, even if they’re accompanied by hot drawn butter and a bib,” he said.

“And unless a crab is a service crab or emotional support crab, and we’re doubtful that is the case here, they must be contained in a sealed carrier at all times.”

And even though there have been past reports of raccoons, cockroaches, and bedbugs hitching an underground ride from time to time, Ross says this was a first.

“I have no recollection of other similar instances,” he said.