Intersting

Decent one-shot. Good work.

*lol* now that I'm starting to think about it, if Dexter really did exist in the world of Phineas and Ferb, I wander what HIS annoying super secret angent animal bent on thrarting his schemes would be. Or is Monkey supposed to be his super secret agent animal in between being a superhero? though Dexter isn't that evil or world taker mindsetty, though Mandark definitely deserves an animal agent to thrart him every now and again. *lol*

That was really sweet. Great story!

There's one spelling error that I noticed and it's actually kind of funny. At the part where it says "well, if you incest", I think you meant "well, if you insist". You might want to look up the word "incest" on Google.

Despite that, I really enjoyed the story.

Aww! I loved it! I'm kinda glad you didn't add Agent P and Dr. Doofenshrimtz (I spelled it wrong, I know!) That kinda explains Phineas' personality and Candace and Phineas' hair color. 'Dee Dee, get out of my la-bore-ato-ry!' Here, have a well deserved cookie.

Really good story

It all makes sense. Apart from the timeline and the whole, y'know, crossover thing, it all comes together. Neat!