Phineas, Ferb & Sonic: Halloween

Phineas, Ferb & Sonic: Halloween is the Halloween special of the Xros-Over Series, with Knuckles being held hostage on Angel Island's Haunted Hill Zone. The chronological prequel is Phineas, Ferb & Sonic: Adventure and the chronological sequel is Phineas, Ferb & Sonic: Christmas Spectacular.

Halloween (Part 1)
A knock was at a door with a sign that says “Halloween in Progress!” Sonic in his Way Past Cool Halloween costume heads to the door to see his friends Phineas, Ferb and Isabella.

“Hey guys, Great costumes!” Sonic tells his friends to see Phineas is dressed like him, Isabella is dressed like Amy and Ferb is dressed like Knuckles.

“Ferb, why are you Knuckles?” Sonic asks and Ferb replies “This is the only costume that was left at the store!”

Sonic takes a look at his list to see Knuckles is the only person he invited not at his party, and then Sonic says “Hey where's Perry?”

Back on Phineas and Ferb's world Perry walks over to a candy basket and hops in. He lands in his lair but a few SugarPopers fell in to.

“Good Evening, Agent P. Dr. Doofenshmirtz is up to some tricks...” a rim-shot is heard, “Carl!”

“Sorry Sir.”

“Well go stop him!”

Perry salutes and hops into a candy cart, and drives to Dr. Doofenshmirtz's base.

(♪Doofenshmirtz's Evil Incorporated During Halloween♪)

“Oh no! Have to keep Warp Ring sealed!” Doofenshmirtz tells himself, when a knocking sound is heard.

“Take a candy.” was Doofenshmirtz's reply, but Perry chatters. “Oh, Perry the Platypus!”

Doofenshmirtz walks over and opens the door. “Oh Perry, look no scheme today! I'm trying to clog the Warp Ring! Dr. Eggman caused nothing but misery, back at collage!

“Good Morning Doc!” Doofenshmirtz tells his roommate, to see Eggman is gone then he looks outside to see loads of Egg Fighters storming the school.

''“Oh great! My Egg Fighters are on a sugar rush!”''

“Hey set the Egg Fighters to “Attack Mode”, and they nearly broke the entire building! So, I'm blocking the Warp Ring so he won't attack this year! Hey Perry can you help me!” Doofenshmirtz asks. Perry just grabs some boards and quickly puts them over the Warp Ring.

“Oh thanks Perry. Hey do you have any SugarPopers? I love them!” Doofenshmirtz tells Perry, he rummages through his hat and pulls some out.

“Oh thanks Perry. So I'll show my Duplic-8-inator 2.0.! It'll duplicate anything 8 times and the 2.0. means it'll double by 2! So it'll duplicate anything 16 times!” Doofenshmirtz tells Perry, he walks over and puts the SugarPopers in front of the inator and gets more.

“Let's eat!”