"Troubled Mind, Part Two: Proof Positive"
*Peter Parker takes a stand! With a villain acting like a hero and a hero acting like a villain, one man has decided that enough is enough! More with Cardiac! More surprises! And a moment that will break a lot of hearts! To save the life of one of Spider-Man’s enemies, Peter Parker fights to regain control of his body, his mind, and his destiny! Is this the beginning of the end for Otto Octavius? *Source: marvel.com
Collected in Superior Spider-Man HC Vol 2 and Superior Spider-Man TPB Vol 2.