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 decide stopping the stampede is what they are going to do today.

This episode is also the first appearance of Vanessa, Doofenshmirtz's daughter.
----
!!Tropes
* MidBattleTeaBreak: Or Mid-stampede tea break.
* MindControlDevice: Doofenshmirtz made loads of small helmets that could fit on the termites.
* SoftWater: Well specifically soft waterslides, that catch the cows that fall of a cliff.
* WhatAnIdiot: [[invoked]]Vanessa really calls out how stupidly her dad made the death trap, when Doofenshmirtz himself isn't calling out his own screw-ups.
----