: Perry the Platypus sneaks off to his secret lair to receive a mission from Major Monogram, marking the first time he foils Dr. Doofensmirtz's "Inator."
: Candace initiates her endless quest to "bust" her brothers by trying to show their mother, Linda, the massive coaster. [S1E1] Rollercoaster/Candace Loses Her Head
(the second half of S1E1) specifically features the family celebrating Candace’s birthday at Mount Rushmore, where Phineas and Ferb attempt to carve her face into the mountain as a "helpful" gift, while Candace nearly loses her mind trying to expose them. : Perry the Platypus sneaks off to his
: The invention conveniently vanishes just as Linda arrives, a staple "helpful" plot device usually caused by Dr. Doofensmirtz's antics. [S1E1] Rollercoaster/Candace Loses Her Head