Goku has taken some wicked lives, the likes of which stand out even more because they’re so few and far between in Dragon Ball.

In appearance, the form is similar to Gogeta's Super Saiyan 4, with long red hair rather than Goku and Vegeta's usual shade of black. Though both are non-canon forms, Super Dragon Ball Heroes ...

Goku turns into Super Saiyan 4, confirming that this form from GT is now canon. This form is slightly different than GT, where the characters had black hair instead of red like in Daima.