Roomba is a random Goomba from a Mario RPG
Random + Goomba = Roomba
Roomba is the opposite of lolchillinz. While lolchillinz represents large amounts of win, Roomba represents fail. A good way to describe this is that lolchillinz = Captain Falcon, while Roomba = Captain Falcon's place on the tier list.
The only thing worst than a Roomba would be The Trophy Master!. Really. Fear The Trophy Master, it's EPIC FAIL!