This is the list of Big Ideas in Season 2.
|"The Lake Nose Monster"||They build a boat to find proof of the existence of Nosey, the Lake Nose Monster.||Phineas and Ferb decided not to reveal the existence of the Lake Nose Monster.|
|"Interview With a Platypus"||They build an animal translator to help all the Danville animals with their complaints, but fail to hear what Perry says (look at notes).||It doesn't disappear, but doesn't work when Linda sees it.||The plan was originally for Perry.|
|"Tip of the Day"||They increase public awareness of the aglet.||Doofenshmirtz intends to erase an embarrassing viral video from every mind in the Tri-State Area, but accidentally erases aglets instead.||This is the first time Phineas, Ferb, Isabella, Baljeet and Buford perform on stage together.|
|"Attack of the 50 Foot Sister"||They help Baljeet win the biggest-watermelon contest at the fair with a growth elixir.||The growth elixir falls into Doofenshmirtz's hands, who thinks it's his dirty nappy smell and puts it in his Smell-inator, causing the whole universe to grow to an enormous size.||Baljeet asked Phineas and Ferb to help him because they helped him with the portal to Mars.|
|"Backyard Aquarium"||They put on a backyard aquarium water show with many different sea animals.||Doofenshmirtz's Hot Dog Vendor Revenge-inator hits the water, freezing it. Candace then leans against it, causing it to slide into the ocean.||The show was put on for Goldie, Phineas and Ferb's new pet.|
|"Day of the Living Gelatin"||They create a giant gelatin mold in Isabella's pool.||The gelatin monster goes down the drain, causing Phineas, Ferb and their friends to believe it's been defeated. However, it was really Doofenshmirtz calling it.||They later try to defeat it due to the mold becoming an evil monster.|
|"Elementary My Dear Stacy"||They make a water slide around Big Ben and the London Eye.||Doofenshmirtz's Big Ben rocket succeeds in a small take off, destroying the slide. the rocket then lands again at Perry's command.||This is Phineas and Ferb's second water slide.|
|"Don't Even Blink"||They make a fun carnival ride that spins you around.||Doofenshmirtz's Invisinator zaps it, turning it invisible. Doofenshmirtz later hits it with his disintegrator ray||Phineas and Ferb make it for the purpose of finding out where their creations disappear to.|
|"Chez Platypus"||They build a trendy exclusive restaurant named "Chez Platypus", which fails to succeed for the new "Badger Restaurants".||A company buys it and takes it away.||Their idea was inspired by a French restaurant Phineas and Ferb found disappointing.|
|"Perry Lays an Egg"||They find an egg they think is Perry's and build a "Platy-posterior" in order to nurture it, but the machine is later replaced by Candace.||N/A||Before they found the egg their plan was to make it the sunniest day possible which didn't change anything.|
|"Gaming the System"||They recreate a video game named "Jump and Duck" to be able to go in the video game.||The final boss exits the game and crushes it.||This is the first time Phineas and Ferb are severely injured, even to the point of death.|
|"The Chronicles of Meap"||They fix Meap's ship in order for him to go back home, after it crashed on earth, and defeat Mitch.||N/A||Before meeting Meap they were playing baseball with a gadget they invented that can control the ball.|
|"Thaddeus and Thor"||They build a backyard fort to see who's inventions are better.||Phineas and Ferb turn the extension off to avoid zoning laws. It's unknown how they took the fort apart afterwards.||The idea of a fort was bought up Linda in the Original Pitch. It also looks like Big Ben from "Elementary My Dear Stacy" with the water slide. This is the first project that Candace made the boys do to compete with Thaddeus and Thor.|
|"De Plane! De Plane!"||They Build a huge airplane made of paper mache called the Paper Pelican.||It lands in water and dissolves.||Later on, When the Paper Pelican descended into the lake, it began to dissolve in the water because it is after all made of paper mache. It was made to beat the Spruce Goose.|
|"Let's Take a Quiz"||The boys create a game show.||Doofenshmirtz's old Shrink-inator hits the set.||Candace and Buford are the contestants in the show.|
|"At the Car Wash"||The boys help the Fireside Girls raise money to save the Star-nosed mole by building a car wash.||Doofenshmirtz's Mountain Out of a Molehill-inator hits the molehill underneath it, causing a giant starnose mole to grow, who (ironically) picks up the car wash and walks off with it.||Jeremy invites Candace for a ride through the car wash in his mom's car.|
|"Oh, There You Are, Perry"||Perry gets relocated to a new nemesis and a new family, so Phineas and Ferb sing a song to bring him home.||N/A||Perry was reassigned his original family and nemesis at the end of the day. This is also the first time they worry about Perry when he runs off.|
|"Swiss Family Phineas"||The family and Isabella get stranded on an island, so they build a Swiss style tree-house.||The nearby volcano 'erupts' with 'pink lava' (Washing-up liquid) and washes it away.||Candace needs to get home in time for Jeremy's party.|
|"Hide and Seek"||The boys shrink themselves, their friends, and their new friend, Irving down to microscopic size to play an indoor game of hide-and-seek.||Doofenshmirtz self-destructs one of his inventions, which happens to be near the machine.||Irving is Phineas and Ferb's biggest fan. He carries a scrapbook of their big ideas with him everywhere.|
|"That Sinking Feeling"||Phineas and Ferb help Baljeet impress his childhood friend from India, Mishti with a romantic cruise.||A lighthouse rocket crashes into it, making it sink.||Mishti is one one of Baljeet's friends from India.|
|"The Baljeatles"||Phineas and Ferb help Baljeet to rock out for Summer Rocks Camp.||N/A||Phineas, Ferb, and Buford become a part of the Baljeatles.|
|"Vanessassary Roughness"||Ferb acquires some Pizzazium Infinionite for Vanessa, but Buford, Baljeet, Perry, Stacy, and Candace are after it too. Phineas relaxes in a massage chair.||Ferb helps Vanessa get the chemical for her dad to prove herself that she's responsible.|
|"No More Bunny Business"||Phineas and Ferb make X-Ray Specs that actually use X-Rays.||
X-Ray glasses: N/A.
|Candace finds a lost rabbit and names it Mr. Cutie-Patootie.|
Carrots: Perry uses a giant lair entrance to make all the carrots they ordered disappear below ground when his lair is taken over by a rogue agent.
|"Spa Day"||Phineas and Ferb create a spa.||Doofenshmirtz's new kitten, Mr. Fluffy Pants, accidentally uses Doofenshmirtz's old Destruct-inator Ray to destroy the spa.||Candace and Stacy also build a house with Jeremy before they go to Phineas and Ferb's spa.|
|"Phineas and Ferb's Quantum Boogaloo"||Phineas and Ferb use the time machine used in "It's About Time!" to go to the future to find a tool that hasn't been made yet. Phineas and Ferb run into the future Candace and her kids.||N/A|
|"Musical Cliptastic Countdown"||This is the first time a new project is seen, since the boys appear for some seconds asking where Perry is.|
|"Bubble Boys"||Create a giant bubble that they can travel through town in.||The bubble eventually pops and they land in the park.||This episode shows that Buford has a soft spot.|
|"Isabella and the Temple of Sap"||Isabella and the Fireside Girls get sap from a tree to help Phineas and Ferb make the bubble.||N/A||Ginger admits her liking of Baljeet. This happened during Bubble Boys.|
|"Cheer Up Candace"||Phineas and Ferb help cheer Candace up with a Mix and Mingle Machine after Jeremy cancels a date.||Debris from Doofenshmirtz's Perry robots cause the machine to spin too fast, destroying it.||In the beginning of the episode, Phineas and Ferb built a replica of The Temple of Angkor Wat out of playing cards.|
|"Fireside Girl Jamboree"||
||The rollercoaster disappears when Doofenshmirtz hits it with his Metal Destruct-inator, turning it into brocolli.||Candace only did it to go to a sold out concert. She really didn't need to be a Fireside Girl because Isabella could bring guests. In order to earn Candace's "Delivering cupcakes patch", the boys build their second roller coaster. (Roller coaster)|
|"The Bully Code"||The boys build a giant contraption that puts the life of Baljeet in great peril as soon as he stands on the X, so that Buford will save his life.||It doesn't disappear; but Linda sees it, thinking it is public art.||They do this because Baljeet saved Buford's life, so according to the bully code Buford becomes Baljeet's slave. Baljeet hated this, so he turned to Phineas and Ferb. Linda sees the boys' contraption but she thinks it's only public art.|
|"Finding Mary McGuffin"||Phineas and Ferb help Candace to retrieve her doll, which was accidentally sold off to Doofenshmirtz, then gives it to Vanessa.||N/A||Vanessa wants it too. The doll was discontinued.|
|"Picture This"||Phineas and Ferb create a transporter after Ferb leaves a skateboard back in England.||Perry uses it to transport Doofenshmirtz's new invention there, which then self-destructs.||They also helped their friends find lost items.|
|"Nerdy Dancin'"||Phineas and Ferb "teach" Jeremy how to dance using a metal exo-skeleton.||N/A||Jeremy and Candace are entered in "Let's All Dance Until We're Sick."|
|"What Do It Do?"||Phineas and Ferb figure out what an invention does using reverse-engineering.||The first rocket takes off after the arm that Perry used to get past the traps accidentally hits a red button. Ironically enough, it promptly falls in love with the second one and they take off together.||It is Doofenshmirtz's anti-romance invention. It landed in Phineas and Ferb's front yard.|
|"Atlantis"||Phineas and Ferb and their friends go to the beach and find the lost city of Atlantis.||When they take it to the surface with giant helium balloons, spines from Doofenshmirtz's evil plants pop them so it sinks again.||Irving is included in the adventure because he went into Phineas and Ferb's car while their mom got gas.|
|"Phineas and Ferb Christmas Vacation!"||
Phineas and Ferb thank Santa by decorating Danville and making a rest stop for him. After the effects of Doofenshmirtz's Naughty-inator, Phineas and Ferb release a song to get the attention of Santa Claus.
|The rest house disappears when Santa takes it to the North Pole and uses it as a clubhouse. It is unknown how everything else disappeared.||Then they save Christmas for the Danville area (which is a typical thing to do in a Christmas special).|
|"Just Passing Through"||Linda loses her guitar pick, so Phineas and Ferb make an orb that goes through anything and then use it to find their Mom's guitar pick.||A steamroller runs it over.||This invention saves Phineas and Ferb's life, by allowing a steamroller to safely pass through them.|
|"Candace's Big Day"||Phineas and Ferb help throw a wedding, for Aunt Tiana and Uncle Bob.||Doofenshmirtz's Junk Food-inator hits it and melts it.||The ice sculpture they make, is destroyed by Doofenshmirtz Junk food-inator because the liquid is warm and so the ice melts.|
|"I Was a Middle Aged Robot"||Candace and Lawrence compete in a competition, so Phineas and Ferb and the Fireside Girls make a blimp to cheer on Candace and Lawrence.||A nail from Doofenshmirtz's plane pops it.||The balloon is run by the energy exercise. The balloon also includes a tube-like "360-Fun Bounce" Lawrence and Linda sees the balloon, but apparently don't care or are not aware it was built by the boys.|
|"Suddenly Suzy"||Phineas and Ferb build a replica of Niagara Falls so they can ride a barrel over it and Phineas and Ferb unknowingly try to bust themselves.||Buford sticks some Tuff Gum to the top, making it stick to Doofenshmirtz's Carbon Footprint-inator.||They get the idea while under the broken sprinkler and Linda mentions that it looks "like Niagara Falls".|
|"Undercover Carl"||Phineas and Ferb build an Anti-Gravity Fun Launcher but Carl intercepts their plans and assumes they are working for Doofenshmirtz, so he is sent undercover to figure out what they are doing and Carl helps Phineas and Ferb build the Anti-Gravity Fun Launcher and use it.||Doofenshmirtz steals it after his one is taken away by the police.||This is the first episode where Carl plays a lead role, and he comes in direct contact with the boys and their friends for the first time.|
|"Hip Hip Parade"||Phineas and Ferb decide to help build floats for all the neighborhood kids in the yearly "Tri-State Area Unification Day" parade.||Doofenshmirtz's Duplic-8-inator hits the balloons above them the floats, so they float away.||Candace was out with Linda all day, and had promised not to obsess about the boys for the day, but seeing the parade go by made the temptation too irresistible.|
|"Invasion of the Ferb Snatchers"||After watching a sci-fi movie marathon, Candace becomes convinced that Ferb is an alien, but it's revealed that Phineas and Ferb built a spacecraft for Garbog, an actual alien friend of Meap's.||
The launch pad that Phineas and Ferb made was wrapped up in a nice little bow, because it was shot by Doofenshmirtz's Wrapped Up in a Nice Little Bow Inator.
The Linda robot controlled by Garbog disappears after he flies off.
|In the end, Ferb is not an alien, and there are logical explanations for all of her proof. For example, Candace thought she saw Ferb's head floating in liquid in a jar, but the jar only contained the liquid and Ferb was standing behind it; and when Candace thought she saw Ferb's head ripped off, but she had mistaken him for a cord in a tent.|
|"Ain't No Kiddie Ride"||Phineas and Ferb trick out kiddie rides at a store.||The rides are taken away and replaced with brand new identical ones.||Candace ends up flying around town uncontrollably, and the boys and their friends have to save her. Ferb literally saved her life while she was plummeting off a cliff by doing the impossible - slingshot a quarter right into the slot on the rocket.|
|"Not Phineas and Ferb"||Phineas and Ferb go to the movies, but Baljeet and Buford pose as Phineas and Ferb beside a giant hologram of the boys' Eiffel Tower construction.||
Baljeet: He turns off the projector.
|This is done for Irving's brother Albert because he doesn't believe that Phineas and Ferb are anything special.|
|Perry: He re-shrinks the Eiffel Tower and lifts it back up.|
|"Phineas and Ferb-Busters!"||Phineas and Ferb create an unlimited power supply to propel a group of cyclone-like vehicles known as "Spinning Tops of Doom."||
Amusement park thing: Unknown
|Candace could've easily busted the boys in this episode, but because she was waiting for a signal from Stacy and Jenny in the backyard (which never came; their headsets were destroyed), the tops disappeared. At the beginning they show an amusement park type thing containing their third Roller coaster. ("Rollercoaster", "Fireside Girl Jamboree")|
|Spinning tops: Buford turns the power supply up to Danger, so the tops end up flying away.|
|"The Lizard Whisperer"||The boys build a giant frozen yogurt machine to last them the summer, later they spy a chameleon and decide to keep him as a pet.||
Giant Steve: Doofenshmirtz accidentally turns on his Gigantinator Ray and shrinks Steve back to his normal size.
|This invention was built at the start of the episode, and quickly destroyed when Steve the chameleon grows to a gigantic size. Ferb gives a really long speech.|
|Frozen Yogurt Machine: Giant Steve steps on it, crushing it.|
|"Robot Rodeo"||The boys host a rodeo with robot bulls.||The bulls are enraged by a red balloon. When the kid lets go of it, the bulls chase it, taking the rodeo with them.||Isabella's hair gets frizzy.|
|"The Beak"||A super villain arrives in Danville to challenge Phineas and Ferb after the boys are mistaken as a superhero (while wearing an indestructible suit they designed to safely conquer their newly built extreme skate-track) known as The Beak. With the super villain wreaking havoc, it's up to Phineas and Ferb to thwart him.||
Skate Track: To stop flying, the Beak uses his grappling hook to latch onto the skate park, knocking it down.
|They initially built a super skate ramp of doom. After realizing the dangers of the ramp, they build the super suit to protect themselves.|
|The Beak Suit: After Phineas and Ferb reveal they're the Beak, Perry uses the suit to defeat Doofenshmirtz.|
|"She's the Mayor"||Phineas and Ferb build an authentic log cabin and a pioneer village using only their dad's antique collection of pioneer tools to do it.||Doofenshmirtz's Accelerate-inator rewinds time and eventually rips it to shreds, creating a new, alternate dimension.||This is fourth time that Candace busts her brothers, though the giant time lapse that Doofenshmirtz caused by his Accelerate-inator made it never happen.|
|"The Lemonade Stand"||After Candace asking them if they could think of something normal to do for a change, they build a very typical lemonade stand and begin to offer franchise opportunities||The robot is cut by Doofenshmirtz's Paper Cut-inator. Lemon juice pours into the cut, destroying the robot, ending the franchise.||In order for Phineas and Ferb to make the lemonade, they made a giant machine that looked similar to a robot, so it could produce the lemonade. It later gets destroyed by Doofenshmirtz's Paper-Cut Inator.|
|"Phineas and Ferb Hawaiian Vacation"||
Part I: Doofenshmirtz's De-Evolutionator, which is set on reverse, hits the A-Primes, evolving them into humans.
|Part II: They help Candace make it to the top of Mount Wa Ta Lot Ta Hoie.||Part II: N/A|
|"Phineas and Ferb Summer Belongs to You!"||Phineas and Ferb build the "Sun-Beater 3000" and fly around the world in one day. The day before they make a jump roping robot.||
Jump Roping Robot: Not shown, but it was caught on the tail of the airplane Doofensmirtz and Vanessa were riding to Paris.
Sun-Beater 3000: It is gradually destroyed as they go along until only the seats are left.
|It's the summer solstice and because it's the longest day of the year.|
|"Nerds of a Feather"||Phineas and Ferb head to the Tri-State area's annual sci-fi/comic-book convention to meet their hero, special effects guru Clive Addison.||N/A||Their plan gets sidetracked when they're swept into a duel between fantasy fans and sci-fi geeks.|
|"Wizard of Odd"||Phineas and Ferb clean the house by spinning it. They later build a giant unicycle.||During the dream, they build several alternate routes for Candace, but she refuses to go on any of them.|
|"We Call it Maze"||Phineas and Ferb build a challenging labyrinth in their backyard.||Doofenshmirtz's Tilt-inator causes it to roll away.||However, Doofenshmirtz's invention makes the labyrinth rolling away.|
|"Ladies and Gentlemen, Meet Max Modem!"||Phineas and Ferb decide to turn his father into "Max Modem", an unknown singer from the 80s.||N/A||Lawrence feels depressed because his wife is going to forget him because she will meet exciting and fun people.|
|"The Secret of Success"||After watching a commercial for an all-terrain vehicle, Phineas and Ferb build a better model - one that can drive on literally any type of surface.||Ferb activates Rocket Mode and flies to the Moon.||The truck turns into a rocket and flies away before Linda sees it.|
|"The Doof Side of the Moon"||Phineas and Ferb decide to build the "World's Largest Building" in order to make Danville more popular.||Doofenshmirtz's Lunar Rotate-inator hits the Moon, which the building is attached to, causing it to fly away.||Doofenshmirtz's invention drives it away.|
|"Split Personality"||Phineas and Ferb create a machine that splits an object into its components, but their cover is blown with Candace and her double one.||Candace accidentally steps on a rock, which really activates Perry's lair entrance, which the Molecular Separator was stood on.||They have to get the two Candaces before they get in trouble.|
|"Brain Drain"||Phineas, Ferb, Isabella and Baljeet are in bed because they're sick and they, along with Buford, play video games that let them compete against another friend.||N/A||Later, they accidentally get the video feed from a junkyard rave where Perry and Doofenshmirtz are fighting. They all control a part of Perry, to fight Doofenshmirtz, thinking it's a Perry based level in the game.|
|"Rollercoaster: The Musical!"||Phineas and Ferb build their rollercoaster from "Rollercoaster" again, but this time, as a musical.||Same as "Rollercoaster"||This is the fourth rollercoaster they've built ("Rollercoaster", "Fireside Girl Jamboree", "Phineas and Ferb-Busters!".)|
|"Make Play"||Phineas and Ferb build a huge jukebox after Lawrence tells them about it.||Doofenshmirtz's Super-Claw-inator picks it up and takes it away.||The jukebox is afterwards used at the opera house.|
|"Candace Gets Busted"||After Candace's "intimate get together" turns into a house party, they eat potato chips while a crowd cheers them on.||Doofenshmirtz's Go-Away-Inator takes away the party, but Perry sets the ray to reverse and brings the party back to the backyard.||Candace asks Phineas and Ferb to stay out of the way, so they don't do anything.|