Super Saiyan X2 is the next form after Super Saiyan X. This form requires deep dark hatred, which is only available to Goku, Vegeta, and Gohan. The form is even less Super Saiyan. As you transform, the form gives you a red-orange light, and changes the sky color to green. The lightning is slightly greener. The aura is also red-orange and also a shade of purple. Your voice gets deeper, similar to what happens to your voice when you go SSJ3. If you have a pure heart, you will slightly get evil, not enough to kill, similar to Super Saiyan 4.
You have to feel almost all hatred, almost no hope, your heart darkening, so much rage. The only people to ascend is Goku and Vegeta, because of the hatred of the Saiyan race extinct. The form has so much mass that Jupiter would be small compared to it.