The Ratman is a local legend originating in the town of Southend-on-Sea, Essex, Englad. Centering around an underpass, the legend has two main variants, the common factor between them being the presence of a rat like creature who appears in the pedestrian walkways at night.
The most commonly told story of the Ratman involves an old tramp who used the underpass to escape from the rain and the cold at nights. The story goes that he was old and barely able to walk. One night a group of teenagers beat him half to death and stole his blanket, the only real source of warmth he had. Dying from his injuries and the biting cold of the night, he succumbed to hypothermia, his stiffening corpse nibbled and gnawed on by the numerous vermin which inhabit the area. Soon after, locals reported odd noises. Namely, high pitched squealing and the sound of nails dragging along the walls.
The other version is far more fanciful and seems to have emerged in schools. The Ratman is no longer a ghost, but a real creature. The story runs that a Mayor of the town was a known adulterer and was eventually cursed for his infidelity, in the form of a grotesque child. A baby with the elongated snout and worm like tail of a rat. The child grew and developed tastes for flesh.
The Mayor had the underpass constructed to conceal his monstrous child. And via hidden doors, the Ratman escapes at night, scaring off any visitors who disturb his rest.