Coffin on Wheels

The Coffin on Wheels is the titular villain of an urban legend / modern ghost story concerning the ancient belief of the angry dead - given a more modern flare, it is not as wide-spread or known as many other urban legends but is often seen as one of the creepier legends due to the macabre nature of the antagonist, which is said to appear as a literal coffin on wheels, sometimes with a propeller to aid it move : the Coffin on Wheels is seen as an unstoppable agent of revenge and once it has began to stalk its victims they are powerless to prevent their terrifying demise, which often climaxes in them being dragged to Hell by the spirit or simply being gruesomely mutilated and killed.

Basic Story
the basics of each story is that one or more individuals are haunted by a sinister voice that speaks via radio, phone or other devices - the voice warns them that "the Coffin On Wheels knows your town and is looking for your home", followed by "the Coffin on Wheels knows your home and is looking for your front door" - then the inevitable occurs as a knocking occurs on the door, no matter what a victim may do at this point the end result is always the same : either the door is opened willingly or the spirit will enter by itself, resulting in the victim(s) coming face to face with a terrifying coffin, driving itself on wheels, the coffin will proceed to open and reveal an undead monster that will then kill, mutilate or even drag a victim to Hell.

Often the victim(s) are criminals who have engaged in acts of murder themselves and the Coffin on Wheels is thus a dark agent of revenge, often the undead monster within the Coffin is the angry soul of the murdered, seeking to punish those who wronged them in life.

This is not always the case though, sometimes a victim is largely blameless of misdeed and the Coffin on Wheels attacks them out of spite, this is much rarer and in most of the standard stories it is vengeful rather than simply malicious.