Dragon Ball Kai (2014) - episode 31 - 08 Nov, 2014

Buu lays waste to another village, turning its citizens into clay in order to build himself a house for a brief rest. Meanwhile, Goten and Trunks, slightly bored from their training, ask Goku to show them his Super Saiyan 3 transformation. However, upon doing this, Goku uses up the remainder of his time on Earth. After saying goodbye to everyone, Goku returns to the afterlife, leaving the Fusion training in the hands of Piccolo. Meeting up with Yemma, Goku is relieved to hear that Gohan isn't dead and decides to follow his energy trail. (Source: Wikipedia)