A bumball is where someone has gone for a shit which it is on the soggy side. With the over use of lavatory paper many pieces break off and roll up into little balls, very often landing on the toilet floor.
I was busting for a poo the other day and had to dash in to the nearest public loo. Unfortunately the place hadn't been cleaned for ages and the floor was littered with bumballs.
The name of the best and most supreme group, cult, tribe and army in the world. You have to be on an elite level to understand the meaning behind the word. Originated in Gloucester, UK.