Perry the Platypus has encountered Dr.D's daughter several times due to his daily battles with her father, Heinz Doofenshmirtz. Despite her being the daughter of his nemesis, and her having helped out with her father's traps and schemes on occasion ("The Magnificent Few", "Tree to Get Ready"), the two get along very well.
Perry has shown a willingness to help Vanessa out if she needs or asks for it. The first time this is seen was at her birthday party. After helping Dr. Doofenshmirtz set up her birthday party, he watched as Vanessa chewed out her father for setting up a party meant for a little girl, not a teenager like her. In the process of defeating Doofenshmirtz, a large firecracker activated and nearly destroyed the entire room. Perry pulled Vanessa to safety under a table, and when the coast was clear, they came out just in time for her friends to arrive, proclaiming the ruined room "the coolest party ever." Vanessa credited both her father and Perry with setting it up, and Perry acknowledged this with a tip of his hat before leaving ("Dude, We're Getting the Band Back Together").
More recently, he has assisted her in concealing her relationship with Monty Monogram from their fathers. Although Perry was initially shocked upon discovering her interest in him ("Minor Monogram"), he has twice helped keep the relationship a secret. The first time was upon Vanessa's request; while on a mission at a coffee shop, Perry noticed Vanessa and Monty there and tried to disguise himself. She noticed him, however, and asked him to conceal the date from her dad; he agreed and wound up spending tireless minutes holding or placing objects between Doofenshmirtz and the couple ("Sipping with the Enemy"). The second time, at the Danville Doo Wop Hop, Perry managed to launch Doofenshmirtz's car into space just before he recognized the boy Vanessa was with ("My Sweet Ride").
However, in spite of this, there were a few times when he doesn't show any concern towards Vanessa at all. At one point, when Vanessa volunteers to help her dad find a rare substance at the mall so that she can prove to him that she is responsible of having a car for herself. Upon eavesdropping on this while being in disguise, Perry ruins Vanessa's chances of getting a car by framing her dad of shoplifting, much to Vanessa's dismay ("Vanessassary Roughness"). Another time was when Perry was fighting Doofenshmirtz in the Tokyo Tower, where he broke Doofenshmirtz's remote, causing a crane carrying a giant balloon on top of the tower to run out of control. The giant water balloon accidentally knocks Vanessa from the tower (much to Doofenshmritz's dismay), but Perry shows no concern of this, as he is more focused on freeing a tied-up Monogram and taking Doofenshmirtz into custody. However, Perry and Monogram are forced to help Doofenshmirtz rescue Vanessa after so many pleads, and they had to travel around the world to do so until they reached Paris. After helping Doofenshmritz rescue Vanessa at the Eifel Tower, Perry takes his opportunity to arrest Doofenshmirtz, but Vanessa retaliates by posing her hairdryer as a gun to stop him, allowing herself and Doofenshmirtz to escape by stealing Perry's hovercraft to continue their vacation, which left Perry really upset. ("Phineas and Ferb Summer Belongs to You!")
When Doofenshmirtz finally succeeds in his goal to take over the Tri-State Area by being elected as its first Tri-Governor, he took the opportunity to draft a law forbidding Perry and the rest of O.W.C.A. to thwart him until his term is over, which left Perry extremely depressed. Despite being aware of her father's newfound success, Vanessa too is depressed as she wanted to have an internship at O.W.C.A. and Perry convinces her to tell her father about the intenrnship and have him see things her way. He then wishes her luck for it. ("Last Day of Summer")
Vanessa knows Perry as a secret agent, not as Phineas, Ferb, and Candace's pet, and all her interactions with him have been during his missions, though there has been a close call which was prevented by Perry becoming unconscious and therefore not coming into view and recognition of the Flynn-Fletcher children and the Doofenshmirtz family ("Night of the Living Pharmacists") . She always greets him whenever they run into each other on one of his missions ("Phineas and Ferb Summer Belongs to You!", "My Sweet Ride"), and she trusts Perry enough to ask him for help in concealing her relationship with Monty ("Sipping with the Enemy"), and thanks him for helping her dad with her birthday party ("Dude, We're Getting the Band Back Together"). That being said, she does hold Perry in high regard, and frees him from a trap when the two of them and Dr. Doofenshmirtz are in danger ("Minor Monogram"). However, there were a few times when she gets really annoyed by Perry's presence. At one time, Vanessa is furious at Perry for participating with her father's plan to overprotect her during a camping, saying that she expected better from him, much to Perry's embarassment ("Skiddley Whiffers"). Also, when Vanessa tries to retrieve a rare susbtance for her father at the mall so that she can get a car for herself, she is extremely furious by Perry's endless attempts to stop her from doing so. ("Vanessassary Roughness")
|The image gallery for Perry and Vanessa's relationship may be viewed here.|