Eight Gates Released Formation

The user opens all of the Eight Gates by puncturing themselves just above the heart, temporarily gaining powers a hundred times greater than their normal self, but will die because of the damage done to their body. Under regular circumstances, the effects of opening the eighth gate will cause the user to crumble to ash, having virtually cooked themselves from the inside-out. This is seen when Might Guy opens all eight gates and fights on par with, and gradually overwhelms Madara Uchiha — the Ten-Tails' jinchūriki at the time — causing Madara to compare his fight with Guy to his fight with Hashirama Senju at the Valley of the End.

Trivia

 * Might Guy survived the after-effects of opening all Eight Gates thanks to Naruto Uzumaki's Yin–Yang Release, however, the damage done to his leg as a result of using Night Guy ended his career as a shinobi.