Gogeta

Gogeta (ゴジータ) is an anime-only character who is the resulting fusion of the two highly powerful Saiyans Goku and Vegeta when they perform the Fusion Dance properly. His voice is a dual voice that contains both Goku's and Vegeta's voices. Gogeta is famous for his amazing power and speed, and is often regarded as one of the series' most powerful characters, along with his Potara Earring fusion counterpart Vegito. 

Goku

Son Goku (孫 悟空), better known as simply Goku, is a fictional character and the protagonist of the Dragon Ball manga series written by Akira Toriyama. He is based on Sun Wukong, a main character in the classical Chinese novel Journey to the West. Goku is introduced in chapter #1 Bulmaand Son Goku (ブルマと孫悟空 Buruma to Son Gokū), originally published in Japan's Weekly Shōnen Jump magazine on December 3, 1984, as aneccentric, monkey-tailed boy who practices martial arts and possesses superhuman strength. At first, Goku is believed to be an Earthling, but he is later revealed to be a member of an extraterrestrial warrior race called the Saiyans.

vegito

Vegito (ベジット, Bejitto; "Vegetto") is the immensely powerful result of the fusion between Goku and Vegeta by the use of thePotara Earrings. His voice is a dual voice that contains both Goku's and Vegeta's voices. Vegito is regarded most for his immense power and speed, and is one of the most powerful characters in the Dragon Ball manga and the animes Dragon Ball and Dragon Ball Z. HisFusion Dance counterpart is Gogeta.