Doofenshmirtz uses mind controlled termites to devour all the wood in the tri-state area, thus making a boom for his aluminum siding business.
In the course of the wood eating rampage, the termites destroy a farm, causing the cows to stampede to the city. Fortunately, Phineas and Ferb are there, and with some help from Isabella, they decide to herd them back where they belong.
This episode is also the first appearance of Vanessa, initially introduced as Doof's uninterested new assistant.
Tropes
- All Girls Like Ponies: As Isabella's about to join Phineas and Ferb in herding the cows through the city, she sees a small, cute white pony, which she uses to ride through the city. Downplayed since Phineas and Ferb are also riding ponies, although theirs look less cartoony and cutesy than Isabella's.
- Ascended to Carnivorism: The cows eat at the mall cafeteria, where a sign proclaims the daily special is beef.
- Breaking the Fourth Wall:
- After Linda insists on taking a picture of the boys riding ponies, Phineas assures the audience, "She means well."
- Happens In-Universe, in the song "On the Trail" (which is part of a movie that the boys are watching in the beginning of the episode):Singer: This sunset's lookin' awful groovy on the trail / 'cause they colorized this movie on the trail
- Butt-Monkey: Candace goes through hell in this episode, whether it being trampled by cattle, falling into a cactus patch, then a snake pit and a scorpion cliff.
- Covered in Mud: Candace trips into a mud puddle as she's running away from the cow stampede. The cows jump over the puddle and avoid her.
- Early-Bird Cameo: Listen carefully during the food court scene and you'll hear the Muzak version of "I'm Lindana and I Wanna Have Fun", which would not be introduced for another couple of episodes.
- Early-Installment Weirdness: Doofenshmirtz tries to kill Perry by lowering him into a lava pit. Nearly every episode afterwards has Doof simply trapping Perry.
- Establishing Character Moment: When Doofenshmirtz introduces Perry to Vanessa, she just says, "Whatever", and puts some music on on her mp3 player, establishing her goth and blasé attitude.
- Formula-Breaking Episode: This is one of the few episodes where the boys didn't build or invent anything that Doofenshmirtz's invention removes all traces of afterward. Instead, the plot started when Doofenshmirtz's invention — his termite controlling helmet — wreaks havoc on the ranch that Phineas and Ferb are visiting, causing all the cows to stampede through the city and Phineas, Ferb and Isabella to try herding them back.
- Funny Background Event: When the cows stampede out of the subway, it causes a pizza-guy to drop his spinning dough on his head.
- Inventional Wisdom: For some reason (which he even lampshaded), Doofenshmirtz installs a "reverse" dial on the back of his termite controlling helmet where he can't reach it; Perry locates this dial and switches it on, causing the termites to turn on Doofenshmirtz and chase him off, averting any further harm to the city.
- Lava Pit: Doofenshmirtz installs one on his lake island lair, which he attempts to lower a tied-up Perry into. Perry manages to break free by swinging his entire body over to a safe spot and letting the heat from the lava burn the ropes that bound him.
- Mid-Battle Tea Break: Or mid-stampede lunch break; the gang and the cows stop by the mall's cafeteria to have a quick lunch before resuming their run through the city.
- Mind-Control Device: Doofenshmirtz made loads of small helmets that could fit on the termites in order to control them.
- Overturned Outhouse: One of the things on the ranch that Doofenshmirtz's termites attack is a wooden outhouse; a guy is sitting inside as the termites destroy the outhouse.
- Preemptive "Shut Up": Candace is a mess by the end, and Mom asks if she's all right, to which she replies, "I so don't wanna talk about it!"
- Save the Villain: The first of many episodes where Perry goes back to save Dr. Doofenshmirtz from his impending doom. Perry activates the self-destruct sequence for Doofenshmirtz's hideout, Vanessa takes the only escape pod, and Doofenshmirtz left his jetpack with Perry so he has no choice but to book it. Perry, realizing that he won't be able to make it, returns to the lair and saves Doofenshmirtz just before the lair explodes.
- Screw This, I'm Outta Here: Vanessa gets angry after finding out Doofenshmirtz's lair has a self-destruct sequence initiated, and decided to leave via the only escape pod.Vanessa: You put a self-destruct button in a death chamber? I'm so outta here.
- Second Episode Introduction: The third episode in terms of production order, which is also Vanessa's first appearance, and Doofenshmirtz's first self-destruct button.
- Self-Destruct Mechanism: Doofenshmirtz's lake island lair has a self-destruct button, which Perry presses after he escapes Doofenshmirtz's trap.
- Shout-Out: The shop that Candace enters is called "Haney's Cow Emporium", after the character of Mr. Haney played by Pat Buttram on Green Acres.
- Soft Water: Specifically soft waterslides, that catch the cows that fall off a cliff.
- Strange Minds Think Alike: During Candace's phone call, she tells her friend, "And she was like 'Oh no, you didn't!', and I was like, 'Oh yes, I did!'" Later in the episode, before Monogram briefs Perry in on his mission, he says to someone else offscreen, "And she was like 'Oh no, you didn't!', and—"
- "Take Your Child to Work Day" Plot: This is how we find out that Vanessa is not just Doof's new assistant, but also his daughter.
- Termite Trouble: Invoked by Doofenshmirtz, who has raised an army of termites that he plans to unleash all over the Tri-State Area, destroying all the wood in the area and allowing him to corner the market on his own brand of aluminum siding.
- Three-Point Landing: Perry enters Doofenshmirtz's lair by leaping off his jet ski and landing in this manner.
- Tyop on the Cover: Doofenshmirtz's lair in this episode has the writing for the company on it as usual, but here it's spelled "Doofenshmirtz Evil Lncorporated". Also, the "Doofenshmirtz Aluminum Siding" signs read "Doofenmirtz Aluminum Siding".
- Weaponized Animal: The underwater entrance to Perry's lair this time is guarded by a shark with a laser beam attached to it.
- Wham Line: Vanessa seems like a generic, perpetually bored assistant for this episode only. Then, after Perry activates the self-destruct, she tells Doofenshmirtz, "This is the worst 'Bring Your Daughter to Work Day' ever."
