Vegito Character Facts

Vegito is the immensely powerful result of the fusion between Vegeta and Goku by the use of the Potara Earrings. His voice is a dual voice that contains both Vegeta's and Goku's voices. Vegito is regarded most for his immense power and speed, and is one of the most powerful characters in the series.
Vegito is a mixture of both Goku and Vegeta's characteristics. He is about the same height as Goku, and his personality is a mix of the two Saiyans. He exhibits Vegeta's cockiness and inclination for taunting others, and playing around with his enemies, wanting them to suffer, but is not as serious, having inherited Goku's easygoing, cheerful nature, easily toying with his opponents. He possesses both Vegeta's strategic mind and Goku's combat intelligence, making him that much more efficient. 
Vegito's hair is more inclined toward Vegeta since it firmly stands upwards and is very dark brown in color. However, he has two bangs sticking out like a downward "V" shape, a trait caught from Goku. When he transforms into a Super Saiyan, he looks almost exactly like Goku. Vegito wears two earrings as result from the Potara fusion, and wears an inverted version of Goku's gi. The inversion is caused by adopting the color of Vegeta's outfit for the external wear, and using the orange of Goku's gi for the undershirt. Finally, he wears white gloves and boots in the same style as Vegeta. He is very similar to Gogeta.
The Potara Earring Fusion used to form Vegito is what Old Kai considers to be the proper way to do fusion, as opposed to the Fusion Dance technique. The resulting fusion lasts forever, even if the fused being removes the earrings. The determination of power levels is complex and more unpredictable than that of the Fusion Dance but in Vegito's case, the rise in power is inconceivably drastic. Vegito has the confidence and fighting smarts of Goku, along with the superior attitude and genius strategic mind of Vegeta. After those two strongest people merge, they become the greatest master in the universe.
Vegito is a fusion formed out of desperation by Vegeta and Goku in an effort to stop Super Buu, an ancient and powerful being whose only purpose is to destroy. 
As a Super Saiyan, he gains a slight increase in muscle mass, bluish-green eyes, very defined golden hair and eyebrows and a golden aura (with occasional surges of blue electricity). Once transformed, Vegito becomes truly unstoppable as his powers soared to unimaginable heights: Super Vegito appears to be well beyond Buu's abilities to defeat and absolutely dominated Super Buu (w/ Gohan, Goten, Trunks, Piccolo absorbed) in battle. He hardly exerts himself in battle (only fighting seriously for a brief moment to stop Super Buu from tearing Earth and the nearby planets apart) and is in absolute control of the fight, even telling Buu to "make [him] use his real power". 
Vegito then begins to completely dominate Super Buu, rendering his attacks useless. Super Buu then liquefies himself and goes into Vegito's body through his mouth. Once Super Buu is inside, he makes Vegito's muscles bulge tremendously and tries to take control of his body. 
Vegito cannot transform into this form willingly, he takes the form of a coffee-flavored jawbreaker after being turned into it by Super Buu. Super Buu turns Vegito so that he can consume him, but Vegito is still able to fight as a small candy. Not only does Vegito retain all of his power, but he is also extremely fast and far too small for Super Buu to hit; thus using an original attack to shoot in Super Buu's mouth and out the back of his throat, unscathed. In the dub, he calls it his "Pinball Attack". However, while this small size gives him a colossal advantage in battle, he is not invulnerable and is unable to use any of his special attacks.