After you defeat Shadow Man, go to MarinHarbor. From the center building, go down the flight of stairs and look closely at the screen. You should see a blur every few seconds. Walk up and talk to it. A little girl will say, "You found it! You take it". You will receive the Geddon3 chip.

After acquiring the Geddon3 chip, put it in your folder with a Repair Chip (preferably a * code chip). Being that it makes all panels, swap panels (which constantly takes your health away). Use the Repair to fix your panels, leaving your opponents to suffer. Note: Have Repair out when you take out Geddon 3.