Dragon Ball GT - episode 18 - 09 Jul, 1996

Trunks comes to and brings Pan back to the spaceship. There, they find that Giru has stolen the Dragon Balls. Meanwhile, Goku takes on the three remaining Sigma Force members. When he proves to be too strong for them, they combine into the Sigma Force Cannon. In this state, both their power and their speed increase dramatically. Goku has some trouble with them, but in the end, he doesn't even need to transform into a Super Saiyan to beat them. General Rilldo, who has been watching on a video screen, gets very angry. He decides to take them out himself, and he takes off toward their spaceship. (Source: Wikipedia)