Goku SSJ4

Super Saiyan 4 is an advancement of the Super Saiyan and Golden Great Ape forms that first appears in Dragon Ball GT, with an updated incarnation of it later appearing in Dragon Ball Daima.

 As part of the Great Ape branch of Super Saiyan transformations, the Dragon Ball GT incarnation of the form is separate from the standard branch of Super Saiyan forms despite being named in similar number. A devastatingly powerful form, it debuts with Goku's awakening during the fight with Baby. Vegeta follows suit during the Shadow Dragon Saga, and their fusion Gogeta is shown wielding it not long afterward.

 The incarnation of the form appearing in Dragon Ball Daima is the successor to the third transformation. It debuted in the final battle with Gomah, having previously been achieved by Goku during his training after the defeat of Majin Buu.