Rat king

A Rat King was the term applied to a cluster of more or less normal rats attached by the tail in some manner, allowing them to achieve a higher degree of consciousness, including considerable psionic potential. It was known to use this power to attract other rats in the hundreds to its lair for protection and other unknown purposes. In some cases the psionic power was enough to effectively enslave people.
On Ulthrane 14th, 1742, a rat king and it's horde were exterminated in Packer's Cave by a party including Juan de Fulmando, Fern the Siegemaster, Jinxi, Krendall Moulerbos, Yagritte Ratreaper, and Ursula Nidonge in Packer's Cave.
The incident in Packer's Cave was said to be the inspiration for the dramatic play with music Terror of the Rat King! performed at Madame Maude Lynn's Theater of Thrills. It opened on 20 Damirin 1742.