Super Saiyan 4!?

Summary
Angered and shocked at the site; Baby remembers his people's downfall at the hands of the Saiyans and says that the Golden Great Ape form is new to him as he goes in for an attack, but Goku knocks him down with ease. Goku uses Fire Breath on Baby and destroys a metro area before resorting his Freeze Breath and freezes half of the city along with Baby's Tower. Goku manages to knock Baby down as he prepares his Revenge Death Ball causing him to drop the energy sphere on himself and results in a small explosion.

Annoyed that he was injured by his own attack; Baby fires Final Flash at Goku, but he simply moves out of the way as he stumbles towards a valley and begins destroy it. Pan tries to reason with him only to be knocked away as Goku's attention is drawn to the moon. Goku goes over to mountain and starts pining at Earth allowing Baby to escape as Pan correctly guesses that Goku has no control over himself. Pan tries to reach Goku and even uses her old martial arts outfit, but he knocks her away.

A picture falls out of Pan's old outfit, and Goku picks it up. As Baby concludes that he can also transform; Goku remembers the photo and begins to take control. Baby orders Bulma to prepare the means for him to transform into a Golden Great Ape as Goku begins to transform. After large explosion and a planet-wide earthquake; Goku emerges in the new form that Old Kai announces as Super Saiyan 4 while Chronoa smiles and quotes that she is glad that Old Kai listened to her.

Goku is baffled by the power, but takes no time to go after Baby and immediately kicks him in the back; sending him into the frozen street. Baby orders Bulma to speed up the process as the two battle it out, but Goku easily overpowers him with each attack before pretending to be injured by each punch. After Baby's Revenge Death Ball has absolutely no effect on Goku; he questions Goku's new powers and Goku admits to pretending to be injure and compares his punches to a love tap.

Goku fires his Kamehameha X10 at Baby, but Baby dodges the attack and tries to punch Goku, but his fist is caught by the Saiyan and is sent flying into the ground with a Dragonthrow. The battle continues on for sometime as Baby voice his frustration and attempts to destroy Goku with his Tuffle Big Bang Flash, but Goku dodges the attack and mocks Baby for not understanding the powers of Saiyan and tells him that he'll never be able to use Vegeta's full potential.

Baby admires Goku's respect for Vegeta as his grabbed by the face and slammed into the ground. Old Kai notices that Goku's attacks are more brutal than usual and notes that Super Saiyan 4 seems to make him more beast-like. They fighting continues as Baby is hit by the Blutz Wave Generator and begins his transformation into the Golden Great Ape Form. Immediately after; Baby begins his assault and uses Flaming Death Ball against Goku; surprising the Saiyan that he can still talk normally.

Baby says that it's his turn to go on the offensive and darts towards Goku.

Differences

 * In Fanga; Baby doesn't pretend to be out of control.

Fights

 * Goku (Super Saiyan 4) vs. Baby (Strongest Form 2/Golden Great Ape)