Dragon Ball Z - Season 1 Episode 35 -

Gohan transforms into the giant ape, much to the dismay of the angry Vegeta. After a grueling battle, Vegeta managed to cut off Gohan's tail, taking away his ability to transform. But, the giant ape fell and crushed Vegeta, leaving him beaten and defeated. Krillin decides to finish the Saiyan, once and for all, but Goku has other plans...