Roughly the length of a size 11 shoe, the briny behemoth also has five smaller oysters attached to it. The cluster weighs in at over 3 1/2 pounds.
"The oyster is still alive and is on display in our exhibition here at the Wadden Sea Centre," Christine Ditlefsen, the Danish biologist who found the oyster, told NPR. "We feed it plankton algae and it eats well, so we hope that we can keep it alive for many years."
Ditlefsen said the mollusk is probably between 15 and 20 years old, but an accurate age determination can't be made until the oyster dies. Oysters can live to be more than 30 years old, she explained.
The Pacific oyster was first introduced to European waters in the 1970s.
While the words "world's largest" have been granted to a number of seafood dinners -- like a 1,000-plus-pound shrimp cocktail or a four-ton bowl of mussels -- the newly crowned oyster is the first living shellfish to hold a place in the Guinness Book of World Records.