From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Gokule (ゴタン, Gotan) is the hypothetical Fusion between Son Goku and Mister Satan using the Potara Fusion. His only appearance in the series is in Goku's imagination, though he is a playable character in Dragon Ball Z: Budokai 2. His name comes from the names Goku and Hercule (Satan's FUNimation dub name) whereas his Japanese name comes from the names Goku and Mister Satan.
Gokule seems to equally resemble both his original counterparts, Goku and Hercule. He has Goku's body build with Hercule's hair style, eyes, and beard. His gi strongly resembles Goku's gi, but with Hercule's boots.
After Goku returns to life and Earth, he finds Son Gohan to be the only remaining strong fighter to fuse with. But when Goku threw the Potara earring to Gohan, Gohan dropped it and when he finally found it he was absorbed by Buu. As the only two beings that were still alive are Hercule and Dende, he imagined what the fusion would look like and which of the two would be better. He chose Hercule, because Hercule had more fighting experience and might make Goku a little stronger. In addition, fusing with Dende would make the Dragonballs of Earth disappear.
Just at the moment Goku said that Hercule would catch the earring and put it on his right ear, Vegeta appeared and Goku used Instant Transmission to find Vegeta and fuse, forming Vegetto. This being the case, Gokule was only a hypothetical character in the anime, and is only seen as Goku's mental image of what the fusion would look like.
- Dynamite Kick: Gokule jumps up and kicks his opponent three times.
- Gokule Miracle Bomber: Gokule attacks his opponent with weak punches so the opponent hits Gokule up into the air and then Gokule comes falling down on the enemy for damage.
- Kamehameha: Attack invented by Muten Roshi. At first the user cups both of his hands to concentrate the energy; then, while yelling Kamehame-Ha at intervals, he charges up, puts his hands to the side of his body, and finally unleashes a powerful Ki Blast.
- Miracle Dragon Bomber – A grapple toss originally used by Goku. Only used if Goku is the one who initiates the Fusion.
- Rolling Gokule Punch: Gokule somersaults and when he stand back up, he punches the enemy in the stomach.
- Trick Beam: Gokule turns around and fires a wavy green beam backwards at the enemy.
- Ultra Dynamite: Gokule releases a fast combo of kicks and punches on his enemy.
- Ultra Spirit Bomb: A big pink and white Genki Dama that is stronger than any of Goku's other Genki Dama variations.