When Worlds Collide

After discovering that a strange planet is hurtling directly towards Danville, Phineas and Ferb set out to avert a disaster, while Buford looks forward to making contact with its alien race. Meanwhile, Dr. Doofenshmirtz hopes to steal the world's largest ball of twine.

Episode Summary
At Doofenshmirtz Evil Inc, Heinz Doofenshmirtz accidentally shoots a giant lazer beam out in the roof of his building into the sky.

Meanwhile, Candace is talking to the phone with Stacy, and then the phone gets cut off because of the lazer beam outside. She blames Phineas and Ferb for it. The lazer beam shoots up in space to a planet, which then starts to move to an unpointed direction. She calls her mother to see, but Linda just sees the boys building.

Songs

 * Whalemingo
 * Double Dutch

The "Too Young" Line
None.

Whatcha doin'?
None.

Perry's entrance to his lair
Sleeping in the lawn chair, Perry instantly gets a call and the head rest pulls down, rolling him through some croquet hoops hitting the stake, where he drops down into his lair.

Background Information

 * This episode takes place right after "Gi-Ants".
 * Candace is only allowed to try and bust the boys once a day.
 * Major Monogram reveals that he wears Seaweed Wrap at Night

Production Information

 * This episode was aired on Disney Channel on Demand on September 7, 2012

Errors

 * Phineas's eyes are pointer in different directions when they built the spring.
 * When the whalemingoes' planet is shot back into space, Buford's hair looks like his 2nd dimension counterpart.
 * When the Second time Perry and Doofenshmirtz touch the Double Dutch machine accidentally, Doofenshmirtz's Panda Designed Slipper disappeared and he began to Double Dutch Barefooted.
 * When the Whalemingo planets lands on the spring, Isabella is walking up next to Phineas, but when she goes to grab his hand, Ferb is between them.
 * When Doofenshmirtz first shows the picture of the World's Largest Ball of Twine only the Farmer is in the shot to the Left side of the picture. When Doofenshmirtz breaks the blackboard the Farmer and his Wife are in the picture on the right side of it.
 * At the end of the episode, Phineas is seen running inside with the others, as perry lands on the deckchair, Phineas is still outside and looks at perry slightly off model
 * If The Bust Accord was signed on May 6th, that would imply the boys started inventing before Summer, which is wrong if what Candace said in Phineas and Ferb Christmas Vacation! is true
 * The Bust Accord said Candace isn't allowed to try to bust more than once a day, but she did that in episodes such as "Rollercoaster", "The Fast and the Phineas", "One Good Scare Ought to Do It!" and "Don't Even Blink".

Continuity

 * Fourth episode where the first scene is at Doofenshmirtz Evil Inc. ("Hail Doofania!", "A Real Boy", "The Remains of the Platypus")
 * Third episode to remain at night the entire time ("Candace Gets Busted", "That's the Spirit").
 * Third time the Shooting Star Milkshake Bar is seen. ("Out to Launch", "The Chronicles of Meap")
 * The Farmer and his wife is seen again.
 * Second time Isabella tries to hold Phineas' hand but instead holding another one by accident. ("That's the Spirit")
 * Third time someone shouts, "My watermelon" ("Phineas and Ferb The Movie: Across the 2nd Dimension", "The Mom Attractor")
 * Second time Perry is trapped by something that wasn't meant to trap him ("Chez Platypus").
 * Second episode to mention roadside attractions. ("Road Trip").

Allusions

 * The episode title is a reference to the 1933 science fiction novel, which was made into a movie in 1951.
 * Avatar: The Last Airbender and The Legend of Korra - The whalemingo is a hybrid species like a majority of the animals in the Avatar universe.

Cast

 * Vincent Martella as Phineas
 * Ashley Tisdale as Candace
 * Thomas Sangster as Ferb
 * Caroline Rhea as Linda
 * Dan Povenmire as Doofenshmirtz
 * Jeff "Swampy" Marsh as Major Monogram
 * Richard O'Brien as Lawrence
 * Dee Bradley Baker as Perry
 * Alyson Stoner as Isabella
 * Maulik Pancholy as Baljeet
 * Bobby Gaylor as Buford