One of my more creative images. A Saiyan Pokemon who is a Raichu/Typhlosion Hybrid. In order for him to ascend to this form from his Quilava/Pikachu stage. He has to use something that has the effects of both Fire & Thunder stones. Absorbing Blutz Waves in his Saiyan DNA and being effect by the evolution energy in his body. Thus ascending to this form.

Once done the first time. He will not need the use of the stones again. He can ascend to it with his own free will.

Saiyan Pokemon do not remain in their Final evolution unlike normal Pokemon. They can only maintain the form for so long before reverting to their previous state. This is a cause of Super Saiyan 4's effect over the evolution.