This cheat is pretty simple. All you have to is buy invulnerability in the pause menu. Then go to the wastelands. There, go into the city and find a leaper. Go to the ocean inside the city and make your leaper jump into the water. You can run around above the water without being harmed by the octopus. If you get of the leaper(in the middle of the ocean) the octopus will pull you down.