(a.k.a. Dr. T.)
AFFILIATIONS: Smithy Gang, Koopa Troop.
CLOSE RELATIVES: None.
SKILLS AND ATTACKS: Quiz Master.
STRENGTHS: High intelligence.
WEAKNESSES: Not very loyal.
Dr. Topper is a green Hammer Brother who's obsessed with trivia and intelligence-testing games. He helped guard Bowser's Keep for Exor and Smithy, but it's unknown whether he did it because he was brainwashed or simply because he enjoys testing people. He isn't afraid of Bowser like the other minions in the castle.
After Smithy was defeated, Dr. Topper was never heard from again. Maybe Bowser gave him the boot!