Dragon Ball Z Kai Season 5 Episode 2

A New Hero, Great Saiyaman, Is Born!

Gohan approaches Bulma, who gives him a transformation watch to hide his true identity. On his way home, Gohan encounters two people driving recklessly. This is where he comes up with the alias "Great Saiyaman", and scares the people into driving more safely on the road. Gohan returns home later that night, where Chi-Chi and Gohan's little brother, Goten, discover that Gohan now has a costume to conceal his identity while fighting crime. The next day, Videl is called in to stop a bus hijacking and handles the criminals, but the bus falls off a cliff, as nobody is driving the vehicle. Gohan uses the alias "Great Saiyaman" once again and pitches in to save Videl and the passengers.