Dragon Ball Z: Atsumare! Gokū Wārudo
Plot :
Atsumare! Gokū Wārudo tells a feature-length story involving time travel leading up to the group's first encounter with Cell (portrayed slightly differently than in the mainstream series).
The plot of the animation seems as though it could be worked into the mainstream series, particularly in the ten days prior to the beginning of the Cell Games. However, in this special, Gohan as a kid actually meets Cell, instead of being a teenager after having trained with Goku in the Hyperbolic Time Chamber.
Once the group encounters Perfect Cell at the end of the game, a heavy punch to the face by Goku is enough to cause Cell to flee and recover from the blow.
Trivia :
Goku meets himself...
Goku almost causes a paradox by getting out of the Time Machine to meet himself as a kid, but Trunks drags him away.
