Jaws the book (1974) claimed that if you use a cookie cutter to punch holes from flounder wings, you can create fake scallops and that these are commonly sold in restaurants:
'I was just looking at the scallops, or what they claim are scallops. The chances are they're flounder, cut up with a cookie cutter.' [...] Hooper's scallops were the size of marshmallows. 'Flounder,' he said after the waitress had left. 'I should have known.'
This meme appears to live on to this day, although often the fake species is said to be stingray (skate) instead.
Are there any documented cases of this happening?