Marvin and Pleakley first met when the latter was still under employment under the Galactic Federation as an agent. They bonded over their interest in Earth, but for very different reasons. While Pleakley wanted to study the Earth as much as possible, Marvin wanted to get rid of it because it obstructed his view of Venus. It took Pleakley several tries to convince Marvin to not do that.
The two "friends" (for lack of a better term) tried to keep in touch in their busy lives. It was difficult sometimes with both doing research and missions, but they managed to occaisionally check in on each other until...
Well, until Marvin met Michigan J. Frog and decided to travel the galaxies with his new operatic partner.
And Pleakley was assigned to be the unwilling partner of the infamous (and imprisioned) scientist Dr. Jumba Jookiba to track down the latter's escaped Experiment 626.
Long story short, Jumba and Pleakley ended up living on Earth with Jumba's Experiment 626 (now called Stitch), Lilo Pelekai (the little girl who adopted Stitch when he was trying to first evade capture from Jumba and Pleakley), and Nani Pelekai (Lilo's older sister). The two became roommates and grew close, forming a pretty deep bond and also pretending to be a married couple as part of their Earth disguises. Which was perfect, because they already acted like an old married couple. Not that they would tell anyone that. Including themselves. (Not until much later, when they would pretty much admit their feelings to each other in private.)
One day, a ship landed in the front yard. It was not a ship of the Galactic Federation, so pretty much everyone in the house was cautious. "Everyone in the house" that day meant Pleakley, who had heard the ship land and was rushing to see what it was, and Lilo and Stitch, who had been watching TV when the ship landed and rushed to the door when they heard a knock.
To the child and small alien's surprise, an alien around their size (if not taller) clad in gladiator garb stood in front of them with a box. The new alien asked if they had found the residence of the noted geneticist Dr. Jumba Jookiba. Cautious, Lilo asked why, to which the creature responded that he had a request for him.
At that moment, Pleakley ran in, wearing (one of) his (many) Earth disguises and hurriedly warning Lilo about not talking to strangers.
But the new alien recognized Pleakley, even under the disguise. And Pleakley recognized the new alien, which he identified as his old friend Marvin.
After some reconnection and explanation (mainly to Lilo and Stitch), Marvin asked Pleakley about Jumba, to which Lilo interjected with how Pleakley and Jumba knew each other. Marvin, now gleefully excited, wanted to meet with the scientist right away. Pleakley told him to wait a while and went to alert Jumba, who was working in his own spaceship. Marvin followed him anyway after bidding the small Earthling and 626 a farewell.
Pleakley was finishing up explaining to Jumba that a friend of his was here and wanting to meet with him when he turned around and was nearly scared out of his wits to see Marvin standing there. [wip]
As it was the intended purpose of their creation, Pipien is a well-rounded singer with an operatic voice. He can also hop and jump like a normal frog would. [wip]
- Pipien's name comes from Rana pipiens, the scientific name for the northern leopard frog.
- Pipien's middle name is their Uncle Pleakley's first name, "Wendy" meaning "brave warrior" in Pleakley's native language. Pleakley hates his first name and had a mixed reaction to finding out that Pipien was partially named after him.