During high school Gohan adopts a secret identity when fighting bad guys. He calls himself The Great Saiyaman. He transforms into Saiyaman with a simple push of a button on his Transformation watch band. Initially Great Saiyaman wears a helmet, but Gohan eliminates this from his wardrobe when entering the World Martial Arts Tournament. Any type of armor is not allowed. His identity eventually get's revealed at the World Martial Arts tournament.
Later The Great Saiyaman 2 joins him, this is the identity Videl assumes after she joined Gohan to fight crime in Satan City. Although Videl already did fight crime she now does it in disguise. Videl is only Great Saiyaman 2 once during the series and during Dragon Ball Z movie 13. She manages to catch 3 criminals and mildly fight Hildegarn.