Noun: An individual wearing a mask of your face, that ambushes you while you're taking a shit and starts enthusiastically fucking you. (in any orifice of the dumpleganger's preference)
One that possesses identic odiferous qualities when producing dung, flatulence &/or sharting as oneself, often referred to as a poop plagiarist.
"Walcott, you dirty dumpelganger, what hast thou eaten!?! You smell as though you've been raiding my refrigerator! Just yesterday I cleared the lobby at the country club with that famous sent & now you have cleared my sinuses with your own!