“rat king” is a rare phenomenon when a number of rats become intertwined at their tails, which become stuck together with blood, dirt, ice, excrement or simply knotted. The animals reputedly grow together while joined at the tails and spread plague
“Rat kings are phenomena said to arise when a number of rats become intertwined at their tails, which become stuck together with blood, dirt, ice, excrement or simply knotted. The animals reputedly grow together while joined at the tails. The numbers of rats that are joined together can vary, but naturally kings formed from a larger number of rats are rarer. The phenomenon is particularly associated with Germany, where the majority of instances have been reported. Historically, there are various superstitions surrounding kings, and they were often seen as a bad omen, particularly associated with plagues
The original German term, Rattenkönig, was calqued into English as king, and into French as roi des rats. The term was not originally used in reference to actual rats, but for persons who lived off others. Konrad Gesner in Historia animalium (1551–1558) stated “”Some would have it that the rat waxes mighty in its old age and is fed by its young: this is called the king.”” Martin Luther stated “”… finally, there is the Pope, the king of rats right at the top.”” Later, the term referred to a king sitting on a throne of knotted tails.
Medieval scholars have suggested that people may have been under the impression that the king was actually one animal with many bodies, with the “king” referring to the animal’s size. Legends have suggested that a “king rat” sat on the tails of the king, overseeing the movement of the animals as they attempted to navigate with their matted tails.
An alternative theory states that the name in French was rouets des rats (or a spinning wheel of rats, the knotted tails being wheel spokes), with the term transforming over time into roi des rats”