"Chapter 31" is the thirty-first chapter of Dragon Ball SD.
Goku takes the field against Bandages the Mummy, dealing an astoundingly easy victory. His next opponent, Spike the Devil Man (not “Ackman”!), uses the dreaded Devilmite Beam, which would actually make him quite the force against later villains if you think about it. Fortunately, guileless Goku is unaffected, so it's on to the final match with a mysterious, masked man….