Before you enter battle with packrat, stack up on thudsluggs and boom bats; it also helps to have the medium ammo bag.

To easily take-out Packrat Palooka, first start by hitting the four generator switches to turn off the generator. Then quickly switch to thudslugg and boombat ammo. Send a boombat onto packrat on top of his platform. Watch it explode to see if he falls off. If he doesn't, repeat the steps. As soon as he's knocked off, shoot a thudslugg at him to knock him away from the stage, and then proceed with a boombat to knock him further back. Repeat again with the thudslugg and boombat, and knock him further away from his platform. If done correctly, you can knock packrat unconscious with about 9 thudsluggs and 9 boombats without ever being hit with a missile or dealing with his friends.