S1·E76 True Colors of the Masked Man

Grabbing onto Goku’s tail, the fox mask man knocks Goku around! But then Goku’s tail comes off!! As Goku is about to counterattack, having lost his weakness, the man quickly surrenders. His identity was Goku’s adoptive grandfather Son Gohan after all!! Goku rejoices in their reunion! Thanks to Uranai Baba, Gohan was able to return from the afterlife for a single day. After the brief reunion, Gohan returns to the afterlife once again!