Everyone had a threshold for dealing with shit and Harry had finally exceeded his.
Amid all the threats and not-so-accidental accidents, Octavius finally made a move. It was only thanks to an overpowered stun-gun Peter made him that Harry escaped. Octavius had gotten arrogant, moved just close enough to get in range, then ZAP. Both Octavius and the tentacles went on a fritz, throwing Harry to the ground. He was lucky to have gotten away with nothing worse than a gash on his shoulder and a mess of bruises from the encounter. But more than anything, it simply wasn't enough just to survive Octavius anymore.
Harry knew - now more than ever - that he needed to fight back. He needed to save himself from this guy. --But how? Even the stun-gun could only do so much.
And then he kept wandering into the study for long periods of time, staring at the mirror, long since replaced to hide the lair behind it once more. The serum was gone. Destroyed. But the weaponry, the materials, the blueprints... all of that was still in there. Granted, he couldn't use any of it as is. It belonged to the Goblin, and Harry wouldn't follow in those dark footsteps. If he wanted to use them, he had to become something else; he had to redesign everything.
...But could he? Harry was no genius, after all.
And yet - while that was true, he was resourceful and creative-- and he did exactly what he set out to do. Not without blunder, of course. There were plenty of mishaps and imperfections, but he had access to the programs, the blueprints, the materials his father had left behind. With them, Harry was able to create a new suit, a new glider, new weapons-- all entirely of his own design. He started out just tentatively flying around in abandoned subway tunnels, building confidence in himself and his tech. Especially trying to keep a low profile. This was just to fight Octavius, he told himself. He didn't need any attention on him; he didn't want Peter finding out until he was sure he could pull this off. And he had honestly meant to avoid heroics-- but then one day, he saw someone in trouble on his way to his makeshift training grounds. It seemed too cruel not to help.
They had been so grateful, and for the first time in a long time, Harry was proud of himself. He actually made a difference! It was an exhilarating feeling.
After that, he made more of an effort to help people before heading off to the subway tunnels. He still tried to stay low-key about it, but a new guy swooping in to save people was bound to get some attention. Today, he was even using the opportunity to test out a new gadget: a snare he'd built from razor bat scraps. It was supposed to lock onto a target and - when within range - break open and shoot out a cord that would ideally restrain said target. He was hoping to figure out a way to tie down Octavius' smart arms with it, but he figured this stupid mugger - trying to take off with some lady's purse - was as good of practice as any. The lock-on feature worked great, but the cord thing? ...Not so much. It just kind of ended up clotheslining the guy more than anything. ...Oops.
Thanks to that, Harry ended up staying behind longer than he wanted to, making sure the woman got her stuff back and that the mugger was properly restrained this time. In a hurry not to draw any more attention to himself than he already had, he was quick to return to his glider and hurtle off into the sky, hoping to get to the abandoned subway tunnels without further incident.