Super Saiyan Goku

Super Saiyan Goku is 's Final Smash in Super Smash Flash 2. Tapping into the vast reserves of his power, Goku transforms into Super Saiyan (超サイヤ人, Sūpā Saiya-Jin) form. Goku's speed, strength and power are increased, and his hair and eye colors change. He can also skip his Super Saiyan 2 form to use the Super Saiyan 3 form, were he is powerful enough to use moves like the Ryū-ken and the True Kamehameha. Super Saiyan Goku is one of the many Final Forms in the game, meaning that he is a totally different character who has more powerful attacks than the regular Goku.

Upon transformation, Goku will cover his hands with both arms as the screen darkens and electricity crackles around him; then he will throw his arms to either side and yell as his hair turns yellow and his eyes green. His transformation has the second largest hitbox that is present during the Final Form transformations of many characters; it is a great yellow explosion in the shape of a flame that deals huge knockback and 18% damage to any opponents within range.

Super Saiyan Goku is one of the most powerful Final Forms in the game - his attacks rely more on brute power in damage and knockback, and he is completely invincible to close to all attacks - only some smash attacks and special moves causes him to flinch. In practical combat, it is close to impossible to KO an experienced fighter in SS Goku's control, but if he happens to be Screen or Star KO'ed, for some reason there are sprites for said screen/star KO's.

Origin
This form originated in the manga series Dragon Ball Z. Tales of the legendary Super Saiyan of old had been passed down for a thousand years, but even among the Saiyans themselves, there was much doubt that such a form ever actually existed. However, in truth, any Saiyan whose power level is above a certain threshold has the potential to become a Super Saiyan. Only those with a calm, still heart (like Goku) are able to turn into a Super Saiyan; and even then, only by suffering an extreme sense of danger, anger, or sadness, can the power actually be awakened.

In Goku's case, witnessing Krillin's death at the hands of Frieza was the key to his transformation.

The energy involved in a Super Saiyan transformation causes the Saiyan's hair to stand on end and turn a golden color. The facial expression is sharpened, and the color of the irises turns to a bright emerald green. A Super Saiyan's power level is 50 times greater than that of his normal form. The massive energies involved cause the emotions to be stirred, making it difficult to remain calm. The transformation has a noticeable effect on the Saiyan's personality. Any Saiyan that has a pure heart initially becomes ruthless and overcome with rage, and any Saiyan that was already ruthless to begin with has his ruthlessness amplified. This is first demonstrated when Goku turned Super Saiyan, when he went from a calm, collected fighter to becoming a vengeful warrior, hellbent on avenging his fallen friend, Krillin, even at his own peril.

There are mightier forms, like the Super Saiyan 2, with multiplies the Super Saiyan level by two, making the warrior 100 times stronger than normal, and the Super Saiyan 3, that multiplies the already powerful Super Saiyan 2 by four, thus making the Saiyan 400 times mightier than normal.

In the non-canon Dragon Ball GT, there is a transformation known as Super Saiyan 4, this form, while gained by unorthodox methods, amplifies the power of the Super Saiyan 3 by ten, thus making Goku 4,000 times more powerful than normal.

In the movie, Dragon Ball Z: Battle of the Gods, Goku has unlocked a transformation called Super Saiyan God, this form grants Goku extreme power that far surpasses that of Super Saiyan 3. In order to transform into a Super Saiyan God one must absorb the powers of 6 pure saiyans. The downside to this transformation is that it has a time limit.