While the adherer is described as having a mummy-like appearance, it is not technically undead. Instead it is a humanoid covered with loose folds of white skin that is said to secrete an adhesive substance which causes weapons employed against it to be reduced in effectiveness and to stick to its body.
The creature first appeared as the gluey in White Dwarf #7 (June/July 1978). The adherer then appeared in the original first edition Fiend Folio (1981). In a review of the Fiend Folio, Ed Greenwood considered the adherer to be one of the monsters in the book which "seem to have no ecological niche, being merely "gamey" party opponents".
The adherer appeared in the Tome of Horrors (2002) from Necromancer Games. It was also updated for both Pathfinder and the Swords & Wizardry games. An expanded entry for Adherer also appears in Castles & CrusadesClassic Monsters the Manual.
The adherer appeared in Paizo Publishing's book Pathfinder Roleplaying Game Bestiary 3 (2011), on page 8. The adherer is also fully detailed in Paizo's Misfit Monsters Redeemed (2010).