The story of the eel super
Fockbek's legend is about Aalversupen (Low German for eel drowning or eel drowning). According to the story, the villagers wanted to breed herrings in Lake Fockbek, for which they poured salted herrings they had bought at the Rendsburg market into the lake. The following year, when they drained the lake water to reap the fruits of their efforts, they found not a single herring left, only an eel lounging in the mud. The Fockbekers concluded that this eel had eaten all the herrings. In the course of deliberations about the cruelest possible punishment for the "malefactor", a villager who had once almost drowned advocated drowning the eel (Low German: versupen). No sooner said than done: As soon as the lake was filled again, the eel was thrown into the water at the deepest point. As he struggled in the water, the people of Fockbek commented: "Look at how he's struggling!" and "He's drowning! He's drowning!"; in Low German: "He versupt! He versupt!", hence "De Aalversuper". To remember the spot where they drowned the eel, they made a notch on the corresponding side of the boat. This mocking story was allegedly invented by the residents of the neighboring town of Rendsburg and was intended to reflect the simplicity of the residents of the neighboring western village. Ultimately, the cause was disputes over fishing rights.
Source: Fockbek.de