Slasher Brown is an evil boy who works with the villains, Cuthbert Cringeworthy, The Inspector, Clint Katzenberger, Vilhemina Slop Bucket, Fatty Fudge, Reg Trademark, Sergeant Slipper and Sergeant Boot.
He was a child in The Beano.
He was an adult as a barber who tries (and fails) to get Dennis the Menace's hair cut in the Dennis the Menace and Gnasher episode, Hair Today, Gone Tomorrow. He is revealed to be Walter the Softy's uncle and has an assistant called Reg Trademark. He also hires many bald henchmen to catch Dennis (but they, as expected, fail).