The wicked stepsister of the dingleberry. Formed when one has diarreah or other digestive ailment, the grundelberry is a vulgar clump of human excrement that forms in small balls around hairs found in the human grundle.
Ex. When one goes to Taco Bell and eats three 1/2 lb Beef Combo Burritos, one will experiance gastro-intestinal defiance leading to grundelberry infestation of the grundel.
Also known as dingleberries, grundel berries are the remniants of poop that have attached to the grundel hairs during the course of wiping oneself after taking a crap. BEWARE: Grundel berries can become very itchy!
When I was younger, my mother always told me, "Make sure to wipe thoroughly to avoid those grundelberries!"