Someone is walking over my grave
A response to a sudden unexplained shudder or shivering.
'Someone is walking over my grave' seems a rather odd thing for a living person to say when experiencing a sudden shudder, so why is it said?
The 18th saying derives from an earlier folk legend that a sudden cold sensation was caused by someone walking over the place that one's grave was eventually going to be. This belief is in line with the workings of people's minds in England in the Middle Ages, in which the distinction between life and death was much less clear than we see it now. There was then an unambiguous belief in the everyday communication between the afterlife in heaven or hell and the physical world of the living. When someone dies in our day and age we a likely to hold a commemorative gathering where we talk about the deceased person. Mediaeval mourners would hold wakes, in which they spoke to the deceased, in the belief that their words were being heard and understood. A person's final resting place would also have been understood to be predetermined and 'someone has walked over my grave' would have been said in the belief that a real person had actually walked over the ground where the speaker would be interred.
The earliest known record of the phrase in print, which is of course an indication of the earliest date that we can prove that the phrase was in public use, is in Simon Wagstaff's A Complete Collection of Genteel and Ingenious Conversation, 1738. (Simon Wagstaff was one of the many pseudonyms of the celebrated writer Jonathan Swift):
Miss [shuddering]. Lord! there's somebody walking over my Grave.
The old folk belief is recorded by the Yorkshire novelist Harriet Parr, who also used a pseudonym, that of Holme Lee, in Basil Godfrey's Caprice, 1868:
Joan shuddered - that irrepressible convulsive shudder which old wives say is caused by a footstep walking over the place of our grave that shall be.
The expression is sometimes found in the form of 'a goose (or occasionally, a rabbit) walked over my grave'. These are later and chiefly American variants and the 'goose' version at least appears to be a back-formation, derived from 'goose bumps/goose pimples' which are associated with a sudden feeling of chilliness.
The modern-day scientific explanation for sudden unexplained shuddering and for goose pimples is that they are caused by a subconscious release of the stress hormone adrenaline. This may be as a response to coldness or an emotional reaction to a poignant memory. Fanciful it may be, but somehow, I prefer the mediaeval version.