The umpleby first appeared in White Dwarf #9 (October 1978). The umpleby appeared in the original first edition Fiend Folio (1981).
The umpleby appeared in the second edition in the Monstrous Compendium Fiend Folio Appendix (1992), and was reprinted in Monstrous Compendium Annual Volume Two (1995).
An umpleby is an eight-foot-tall creature covered in wild, straggly brown hair. The umpleby stores large quantities of static electricity in its body, which is releases by touching its victims.
Trenton Webb, in his review of Monstrous Compendium Annual Two for British RPG magazine Arcane, called the shambling umpleby "without a shadow of a doubt" the star of the book: "Effectively a Bigfoot whose wooly hair generates shocking levels of static electricity, these hulking eccentric simpletons will test any parties patience and ability to save against cuteness." Webb also added that even without the umpleby the book "would be a necessary resource for all mainstream refs. With the shaggy-haired one, though, it rapidly approaches the essential."