For international viewers searching there is occasional confusion due to different airing orders. Here is the critical distinction:
Dr. Doofenshmirtz creates the "Ugly-inator" to make everyone in Danville uglier than himself so he can be the most handsome person in the city. Key Production Details Production Code: 115. Original Air Date: May 24, 2008. Phineas y Ferb 1x18
"Phineas and Ferb" season one, episode 18, titled "Crack That Whip / The Best Lazy Day Ever," contrasts a high-stakes roller derby project for grandma with a comedic, subverted day of inactivity. The episode is noted for featuring the first Doofenshmirtz invention without an "-inator" suffix and the musical number "Do Nothing Day". For more details, visit Apple TV Crack That Whip / The Best Lazy Day Ever - Apple TV Key Production Details Production Code: 115