I heard about a horrible river dragon that lurked in the waters under the old London Bridge and destroyed passing boats, eating the crews and passengers.
It started with a small punt and two people out fishing, pushing the punt through the river by use of a long pole. The pole had tapped the dragon on the nose, waking it from it's slumber, where it emerged from the river and dragged the helpless fishermen to their doom.
Following that, it's hunger was insatiable, it attacked a cattle boat, not only killing and devouring the entire crew, but every last bull, cow, and calf sailing on the river.
Finally, a group of brave knights lured it up onto the banks and, with great loss of life, managed to slay the horrible beast. While After the conquest, Sir Newt suggested that they grind up the foul beast and use it for food in the local orphanage to cut down on the wasteful cost of gruel. Thus Dicken's opening line..."It was the beast of Thames, it was the wurst of Thames."
A German farmer with relatives in the US sent them a package consisting of some sausages made from the dragon. When they complained that the package had not yet arrived, he wrote: "Cheer up. The wurst is yet to come."