A male known as a "Colostomizer" is a particularly bad-a motherfucker, specifically with respect to his relative skill at any of a number of competitive endeavors. Whether it be videogames or basketball, a Colostomizer will fuck you up so badly that, once he's done with you, you'll be in desperate need of a colostomy bag
(read: your asshole will be loose to the point that you can no longer control when you take a shit).
Man, you just got owned by that Colostomizer! Seriously, it's like a Greyhound bus just drove straight into your asshole and kept on going!