A group of turds that are hard and mainly round in appearance. They tend to accumulate in the bottom of the bowl and look much like rabbit poop. Most Grivillican poo sessions are ended with little or no wiping required. Main causes of Grivillican poop are dehydration, V-8 overdosing, a diet rich in processed cheese, and lack of exercise.
"Jordan, did a rabbit sneak in the house or did you drink too much V-8? That toilet is full of Grivillican turds!"