One Good Scare Ought to Do It!

One Good Scare Oughta Do It! is the title of the USA unaired 11th episode, supposedly airing around Halloween. It is unaired in the US, but it was aired in several other world locations and on the Fast and the Phineas DVD.

Summary
This episode revolves around Isabella getting cursed with a bad case of the hiccups. So, Phineas decides to build her a super haunted house to scare 'em out of her. Meanwhile, Perry the Platypus stops Doofenshmirtz from destroying his old mentor's hideout, and Candace tries to go to Jeremy's house, but his evil sister Suzy stops her.

The episode starts of with Candace talking into a banana, pretending it's a telephone and it's Jeremy on the other end. Linda walks by, telling her she's going out and asks if she's going to be talking into that banana all day.

In the backyard, Phineas and Ferb are using a "mariachi tree" to entertain themselves, as Isabella walks in, trying to say her catch phrase, but is cut off by her hiccups. Phineas tells her that's one bad case of hiccups and tells her they need to scare them out of her, and asks her what she's afraid of. She tells him that she was afraid of a haunted house at the fair once, and Phineas decides to build a super one.

Meanwhile, Perry enters his lair(through the trash can; first the wrong one though) and is informed that Doofenshmirtz has disappeared. He gives him two reasons: Magic elves transporting him to an angry corn land, or being at an island with a giant "D" on it at the exact coordinates they lost his trace at. He then tells him to forget the first one, and to get onto it. He then runs off to his ship, and an extended version of his song plays.

Candace walks into the backyard as Phineas and Ferb are still planning. She calls them freaks and is told of their plans. She then goes into the house to call their mom, and the number she calls is: Jeremy's! She does the "breaking up" bit where she crumples paper and then screams silently.

With Perry, he is flying over Doofenshmirtz's lair.