[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.
: This episode introduces Phineas’s iconic catchphrase when he notices Perry has disappeared. [S1E1] Rollercoaster/Candace Loses Her Head
In the pilot episode of Phineas and Ferb , several "helpful" recurring features and tropes of the series are established: (the second half of S1E1) specifically features the

