Xiao long xia season has arrived and the city is tearing these little crayfish limb from limb.
It's not pretty but it sure as hell is tasty, and on any given street you can see hitherto civilised people jostling and pushing their way to the front of queues that lead into the bustling canteens where the little crustaceans are being served.
This is not a rarefied experience. After waiting half an hour for a spot, you get marched to one of the formica tables and are packed in, sat down and given a menu.
On said menu there are 20 or so styles to choose from, from spicy hot pot to salt and pepper fried to steamed to braised with a kind of black bean sauce.
All come in one jin (half kilo) servings and all get wolfed down faster than you can say, "Well I always found them a bit fiddly." When the metal trays arrive it a case of rip, dunk in vinegar and crunch and suck.
Fortunately you get issued with a bib, because everything goes everywhere. I have never shied away from messy eating experiences but this is communal troughing like no other.
At crayfish restaurant Fu Mao, the packed room does at least also get issued with a dog bowl for your scraps - the height of decency when it comes to xiao long xia.
At one place we nervously peeked into I saw three men and a woman around a table literally sitting in piles of crayfish. Their shoes were kicking around in a four-inch deep battlefield of torn shells, oily chillies and dirty napkins. It was gross, but upon their faces there was pure delirium.
It is incredible to calculate how many of the little darlings the city gets through in the peak two or three month session. Where we were tonight it was raucous even on a Monday, with two hundred covers or so passing through and each person eating about a kilo, often more.
Perhaps that is why rumours have started that some of the less reputable joints catch their crayfish from Shanghai's surely enormous (and probably fairly easy to access) sewer system.
Ironically the latest Teenage Mutant Ninja Turtles film has just hit the cinemas here, perfect timing for one set of heroes in a half shell to rise up from the underground.)
Indeed I have heard lots of reports of people getting ill the day after. But I have also heard lots of people say, "Well who cares if i get a little ill, they taste so good." Now you know you have hit culinary gold if you get your guests talking like that.