Gotenks was formed when Goten and Trunks did the fusion dance. Gotenks is a powerful fighter but could not really show his full potential due to the fact that he is an arrogant person. After first being formed he heads over to fight Buu where he gets beaten up. Gotenks makes most of his moves with stupid names like 'Rolling Thunder Punch' and 'Ultra Buu Buu Volley Ball etc. He was able to reach SSJ3 but he was also absorbed by Buu. After DBZ finished we no longer saw Gotenks any more.

Name: Vegetto
Characters Combined: Vegeta, Goku

Vegetto was formed when Goku and Vegeta used the Potarra Earings. He is probably one of the most powerful characters in DBZ since the two best fighters are combined. Originally Goku was supposed to fuse with Gohan but since he was absorbed by buu Goku had to fuse with Vegeta. They kicked buu's ass pretty badly and got absorbed purposely to save Gohan, Trunks, Goten, and Piccolo.

Name: Gogeta
Characters Combined: Vegeta, Goku

Gogeta was formed when Goku and vegeta did the fusion dance. Gogeta is even more powerful than Vegetto. He was first seen in movie 12 to battle Janemba. At first Vegeta screwed up on the fusion dance and they transformed into fat Gogeta. They got beaten up pretty badly but 30 minutes later the fusion wore off and they did it right and kicked janembas butt. Gogeta also appeared in GT.