The M Flies is the official graphic novel prequel to the movie. It was written by Tom DeFalco & Robin Etherington.
The M files tells the Background on the monsters and a prequel story named Brain Pain, in which B.O.B. lacks a brain, so through experimentation Dr. Cockroach makes him one. The Smart B.O.B. renames himself "Bartholomew Organo Benedict" and pontificates using large words and phrases. Unfortunately, dues to some miscalculations the B.O.B. brain experiment doesn't go quite as planned.
Contrary to the description on the back, Susan doesn't make an appearance.