The Knucker was a kind of water dragon, living in what were referred to as knuckerholes in Sussex, England. The word comes from the Old English nicor which means "water monster" and is used in the poem Beowulf.
The most famous Knucker lived, according to legend, at Lyminster. The Knucker apparently caused a lot of trouble, consuming local livestock and even villagers, and so it was decided to slay the monster. A number of different legends recount how this was done.
One version has the dragon slain by a knight-errant after the king of Sussex offered his daughter's hand in marriage to whoever rid them of the beast. Legend says that after marrying the princess, the knight settled in Lyminster and his gravestone, the Slayer's Slab, can be seen in Lyminster church.
An alternative legend has the dragon outwitted by a local farmer's boy, called Jim Pulk or Jim Puttock, said in some versions to be from Wick, after the Mayor of Arundeloffered a reward. He killed the dragon by cooking it a giant poisoned pie, which he took to the knuckerhole on a horse and cart. The dragon ate up pie, horse and cart. When it had expired the boy returned and cut off its head. In some versions he then dies himself, probably of the same poison he used on the dragon, though this is possibly a later addition designed to explain the Slayer's Slab.
It was believed that knuckers could be found at knuckerholes in various places in Sussex, including Lyminster, Lancing, Shoreham and Worthing.
The knucker is one of the various dragon species included in the Dragonology series of books. Here, it is depicted as being long, thin and having small wings as well as four legs.
The Knucker appears in Sláine in the British comic 2000 AD.
Knuckers are mentioned and a part of the book series, The Sea of Trolls, by Nancy Farmer. Knuckers play a large role in the second book, The Land of the Silver Apples.
In the PBS animated series Dragon Tales, the characters Zak and Wheezie live underground in a "knucker hole".
- The Knuckerhole in Lyminster supposedly was measured for depth recordings. However, the depth readings found it to be bottomless.