It started off as an average morning in Danville. The Flynn-Fletchers were eating breakfast as usual, but Perry refused to eat his food.

"What's wrong, Perry?" Phineas asked. "Don't you like this brand?"

"Gyururururururu," Perry angrily said, pushing his food bowl away from him.

Phineas looked confused. Yesterday, Perry was acting fine. He ate his breakfast, vanished, and came back just in time for dinner.

"Are you okay?" Phineas asked, putting his hand on Perry's forehead. "Do you feel ill?"

At that moment, Perry turned around and used his hind legs to kick Phineas right in the gut, poisoning the 11-year-old boy. The rest of the Flynn-Fletchers were surprised. Ever since he was adopted, Perry NEVER used his venomous spurs on anyone in the family.

"Why, Perry?" Phineas asked, his voice in a low whisper. "Why did you attack me?"

Later That Day...

Perry arrived at DEI, when Doofenshmirtz was waiting for him.

"Perry the Platypus, what took you so long?" Doofenshmirtz asked. "You were supposed to arrive a half an hour ago."

"Gyururururururu," Perry said, looking annoyed.

"I don't care if something bad happened this morning," Doofenshmirtz said. "Just help me with my latest -inator. Now that I managed to zap you with my Turn-Everything-Evil-inator yesterday, taking the Tri-State Area is going to be easier than I thought."

Although Doofenshmirtz and Perry never actually succeeded in taking over the Tri-State Area, that one day greatly affected the Flynn-Fletchers.

Isabella no longer came over and say her catchphrase, leaving her greatly depressed. However, eventually fell in love with Ferb, who was able to cheer her up and keep her happy.

Candace will never have to worry about another Big Idea, allowing her to have a normal teenage life. She quickly got over the tragic event that scared her life when she was a toddler and she was no longer seen as an insane girl by others.

Linda felt horrible for about a week. But with Lawrence's support, she eventually felt better and moved on.

Ferb was no longer trying to hide his emotions. He vowed to himself to treat Isabella like a lady with great respect and make her feel special every single day. And he'll always remember that when he looks at the tombstone underneath the backyard tree, which was engraved with a single phrase.

RIP Phineas Flynn
The Boy Who Dared to Dream