(MudMan tells 'em 'bout it from issue 10, Creet)
The body of this slow-talking, fault-finding cultural critic draws dust and dirt molecules to itself as if possessing the gravity of the sun. Also unfortunately born a sweaty, sweaty man, the accrual of this debris gives him the appearance of being covered in mud. Dungeon master. Lover of graph paper. Encyclopedic knowledge of b-movies like Robot Holocaust, Robot Monster, Plan 9 from Outer Space, The Abominable Dr. Phibes, etcetera etcetera. Quietly decisive in moments of crisis. 8-bit Nintendo expert. Host of late-night cable access TV movie show. Probably, honestly, the coolest guy in the house. Basement bedroom, just past the washer and dryer.
(MudMan explains it all from issue 3, the Cold Beer War)