You have the option to place as Patrick Star, Spongebob’s best buddy, in Spongebob Squarepants: Battle for Bikini Bottom–Rehydrated To unlock him, you need to save him in Jellyfish Caves after making your way through Jellyfish Fields.
After getting to Jellyfish Caves, have Spongebob use his tongue to move down the slope of sand to find Patrick on a high cliff. To arrive, you need to click the 3 buttons safeguarded by robotics and duplicators. The duplicators will regularly create robotics for you to fight in the middle of the area.
Each of the buttons needs you to jump throughout these small platforms to reach them. Your best bet is to go to the button of the right and after that left before striking the final one directly in front of where you start the encounter. Make sure to take out each duplicator you find at the buttons. Each time you reenter the main area to activate another switch, you will need to fight a handful of robotics, some of them will have a large hammer. Use your attack button when approaching them, and you should be able to knock them away before they do any damage.
When you hit the final button in the middle, 3 platforms will rise in theback You can use them to make your way over to Patrick, where you will now manage him. He also has a golden spatula for you. After you pick up the golden spatula, you can switch in between him and Spongebob using a bus station for the rest of the game.