In the latest character trailer for Dragon Ball FighterZ, Vegeta shows off his Super Saiyan God Super Saiyan form.
The new form adjusts Vegeta's moveset to focus on power moves and adjusts his supers for different attacks and angles than his Super Saiyan form.
Some of you might be wondering why Vegeta is blue and why anyone would possibly name something Super Saiyan God Super Saiyan. I can't answer the second one, but I'll cover the first. When Goku confronted Beerus and got really, really badly defeated, it was reasoned that a ritual involving six Saiyans could transform him into the Super Saiyan God, a form with pinkish skin and red hair. It worked and Goku was able to fight more evenly against the God of Destruction. The blue form, Super Saiyan God Super Saiyan, is the Super Saiyan form of that God ascension, which both Goku and Vegeta achieved after training.
It is never explained how and when Vegeta became a Super Saiyan God as he handwaves it by saying he did it through training as well and no one questions it. In Dragon Ball Super, the form is simply shortened to Super Saiyan Blue, but FighterZ is using the Return of Freeza movie name of Super Saiyan God Super Saiyan.
The short trailer for the form is below.
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Dragon Ball FighterZ is releasing on PlayStation 4, Xbox One, and PC on January 26.