While the boys create an advanced set of x-ray glasses, Candace finds a stray rabbit and adopts him. The rabbit, however, is Dennis, a former OWCA agent who went rogue, and Perry must stop him before he causes trouble.
Tropes:
- Aliens Steal Cattle: When Phineas looks inside a house with the x-ray glasses, he notices a group of aliens experimenting with a cow, causing it to levitate.
- Artistic License – Biology: Dennis has pads on his feet, something real rabbits do not have.
- Bait-and-Switch: At the end of the episode, it appears that Major Monogram is going to give Perry a medal for defeating Dennis, but it turns out that he's actually swearing in Planty the Potted Plant as a member of the O.W.C.A..
- Balloon Belly:
- Dennis becomes massively obese after eating the entire truckload of carrots that fell into Perry's lair. Also doubles as Artistic License – Animal Care, since too many carrots are poisonous to rabbits.
- Buford also has one during the song "X-Ray Eyes"; when Phineas takes a look inside his belly, he sees an unrealistic amount of food inside as well as a "#1 Eater" ribbon.
- Bitch in Sheep's Clothing: Dennis may seem cute, but in reality he's a mean Rogue Agent.
- The Cameo: Linda only appears briefly in this episode when she sees "Mr. Cutie-Patootie" and figures that Candace got a new pet.
- Complexity Addiction: Phineas offers to rescue Mrs. Garcia-Shapiro's wedding ring from the sink and asks Ferb to get a blowtorch and a tub of mayonnaise, but Mrs. Garcia-Shapiro instead wants to call her regular plumber, since he is bonded.
- Crazy-Prepared: Since the glasses take hours to dry, Isabella puts them in her Quick-E Bake oven so they only take five minutes; as she states, "Fireside Girls are always prepared."
- Creator Cameo: The archaeologist who uses Phineas' x-ray glasses to dig for bones is Jeff "Swampy" Marsh.
- Cuteness Proximity: Dennis when in pet mode looks undeniably adorable, which he uses to get Candace to take him inside the house.
- Epic Fail: Doofenshmirtz has always been a Harmless Villain, but him getting defeated by a fucking potted plant shows just how deep his ineptitude is.
- Foul Ball Pit: The boys use their x-ray goggles to look for and then fish out Balthazar Horowitz from a ball pit.
- Free Prize at the Bottom: Phineas uses the x-ray goggles at the store to find the cereal box with the biggest prize (about as big as the box, in fact).
- Freeze-Frame Bonus: While waiting for Perry to arrive, Doofenshmirtz is reciting lines from a bound script book of things he'll say to Perry when he arrives thwart him for the day, and takes note to improve. While the middle paragraph is what he previously recited, the top paragraph are the stage directions for the episode (or rather describing the establishing shot of the Doofenshmirtz building), meaning he has the script of the episode itself.
- Inanimate Competitor: While Perry is away fighting Dennis, Doofenshmirtz puts a hat on a potted plant, naming it Planty the Potted Plant. Doofenshmirtz ties it up with a hanging rope and does his usual routine, as he does with Perry. He accidentally pushes Planty back, causing him to swing back and forth on the rope, repeatedly hitting Doofenshmirtz until he is forced to admit defeat.
- O.O.C. Is Serious Business: The normally upbeat and cheerful Phineas is offended when Candace calls the big idea "stupid".
- Self-Disposing Villain: Doofenshmirtz gets thwarted all by himself without Perry being involved at all (see Inanimate Competitor above).
- Start My Own: The boys decide to make their own x-ray glasses after ordering a pair of novelty x-ray glasses from a comic book that don't work.
- Visible Odor: Apparently, the carrots' scent is so strong that they are represented by orange steam and catch the attention of Dennis. This is lampshaded by Baljeet in the character commentary.Baljeet: You know, you cannot see smell! I just want everyone to know that. It is not possible.
- Welcome to My World: Candace says this to Phineas after he turns away and an entire truckload of carrots disappears.
- What Happened to the Mouse?: Ferb and Isabella disappear from the third half of the episode on. We also don't know if the boys still have the glasses after the episode.
- Wingding Eyes: Candace's eyes have hearts in them when she sees Dennis.
- X-Ray Vision: The whole point of the Mail-Order Novelty glasses the boys get. When it doesn't work, they decide to build their own.
