Role in series
The Pi-Rats first appear in the episode "Piratsy Under the Seas." Chip 'n' Dale run into them when they capture some of the trash that were on the boat the Rescue Rangers were in. The Pi-Rats welcome the chipmunks and invite them to dinner. They later make Dale search for the treasure. When Chip tells them that he and Dale are going back home without the pirates' treasure, Jolly tells them that they stay in their ship forever. When the Pi-Rats trap the chipmunks, Monty shows up disguised as a pirate, with Zipper disguised as a parrot, to order them to free Chip and Dale. The Pi-Rats later find out that it was Monty in disguised when they brought cheese for the mouse to take home. The Pi-Rats make the Rescue Rangers walk the plank where Billy the Squid is waiting for them, but the group escapes and fights the pirates. After the rangers blast a cannonball, the ship gets out of the water and turns upside up. After that, the Rangers and the Pi-Rats say good-bye to each other.
The Pi-Rats make their second and last appearance in "Chipwrecked Shipmunks." In this episode, they run into the Rescue Rangers again and then go look for treasure in a cave shaped like a crocodile head. Dale and Monty get the treasure before they do, making them capture the Rescue Rangers. Dale and Monty make the Pi-Rats follow them so that they can save everyone from a hurricane. The hurricane makes the pirates' ship stand on a rock. When the hurricane is over, the Pi-Rats receive their treasure.