A "rat king" refers to a phenomenon where a group of rats become intertwined at their tails, often due to factors such as entanglement from twine, sticky substances, or ice. The concept of rat kings is often considered a curiosity or myth, and reports of them are quite rare.
In folklore, rat kings have sometimes been depicted as a symbol of disease or filth, and there are various interpretations and stories associated with them. The phenomenon is not well-documented in scientific literature, and some researchers question the likelihood of such occurrences happening in the wild. Rat kings have also appeared in various works of fiction and art, contributing to their mystical and somewhat morbid reputation.