The squid, which was itself more than three feet-long, was caught in the shallow waters off Guangdong province, China, and taken to the fish market in Jiaoling county.
“This sort of squid lives close to the shore and normally makes a meal of small fish and prawns,” said the fishmonger, who gave his name only as Mr Huang to the local Guangzhou Daily newspaper.
“Perhaps he thought the bomb was his favourite food and gulped it down. He certainly had a big belly when he was caught,” he added.
The bomb weighed around three pounds and was shaped like an aubergine.
Local police suggested it might have been dropped by a fighter jet but did not date it.