A Doomba is a death dealing floor
cleaning robot. A Roomba (the popular floor cleaning robot) is
outfitted with various
dangerous items taped to it such as knives, cats, saw blades and blow guns.
"Dude
what the fuck is that thing on your floor! It almost shanked me on my way in." "Oh dude, that's just my Doomba, it's a floor cleaning/home security robot,
I'm going to enter him in Battle Bots next week"
The Doomba is
excellent with getting away with its crimes as it cleans up after.