References in Milo Murphy's Law
In many episodes background characters that appeared in Phineas and Ferb can be seen, though some have a different color scheme.
In "Going the Extra Milo", the bridge Zack and Milo attempt to reach is on Maple Street; Phineas and Ferb live on Maple Drive. The school that Milo attends is revealed to be called Jefferson County Middle School. A race track ("The Fast and the Phineas") and an art gallery ("Oil on Candace") in Phineas and Ferb have a title with the same dedication.
In "Rooting for the Enemy", at the football game - after talking about the French food being sold - the notice board on the football field reads "Great Googly Moogly!", which is repeated by Melissa, after the Geckos score their first goal of the game; this is commonly said by the Phineas and Ferb character Major Francis Monogram. When Milo is being carried from the field, one fan comments that the game "it's like Football X-7", the fictional sport for which Phineas and Ferb constructed a stadium in "My Fair Goalie".
In "Sunny Side Up", as Milo, Zack and Melissa were making a protective shell for the egg drop challenge, one of the projects hit the same pigeon from Phineas and Ferb that had a running gag of flying into their taller inventions.
In "Worked Day", Balthazar Cavendish and Vinnie Dakota's mission involves them traveling through Danville, the primary setting of Phineas and Ferb. A Ducky Momo key-chain, the same as the keys to Candace's car in "My Sweet Ride", was pulled out of Eileen Underwood's pocket by the MRI magnet. Dakota watching the lava lamp was reminiscent of Doofengung from "Tri-Stone Area", one of the characters that Povenmire has previously played.
In "Murphy's Lard", Melissa reveals that she is afraid of roller coasters, because on the first day of summer, one fell from the sky and crushed a science project of hers. This was actually Phineas and Ferb's first titular creation from that series' premiere episode, "Rollercoaster", which was carried off by a helicopter carrying a super magnet due to the actions of Perry the Platypus.
In "The Substitute", there is shown a zoetrope of the magical old-timey bathing suit that lives in the Himalayas known as Klimpaloon, a reoccurring entity in Phineas and Ferb. Klimpaloon also appears later in the episode with his fellow zoetroper as Ms. Baxter flies through space. The element Pizzazium can be seen on the periodic table of elements that Cavendish and Dakota hide behind, placed on the table as it was in the documentary shown during the Phineas and Ferb episode "Vanessassary Roughness".
In "We're Going to the Zoo", Milo is revealed to have pajamas that resemble Perry; Sara specifically comments on the fact that they are teal, as real-world platypuses are brown. Milo and Zack donate their clothes to the Tri-State clothing donation drive. The abandoned ski slope they roll down is labeled "Danville Ski Slope". One of Brigette Murphy's vintage tee-shirts holds the logo of the Phineas and Ferb 80's band Love Händel. Vinnie Dakota also says " There's squirrels in my pants." It's a reference to the song of the same name from the episode "Comet Kermillian" - with the melody of that song too.
In "Battle of the Bands", Slash, who was in Phineas and Ferb The Movie: Across the 2nd Dimension, made an appearance as a judge for the Battle of the Bands. Also, the Lumberzacks were said to have toured malls across the entire Quad-State Area, which was the region that Perry the Platypus was temporarily reassigned to in "Oh, There You Are, Perry".
In "Missing Milo", during the song I Can't Find You, the girl in the shop is holding a Ducky Momo book. An instrumental version of "Let's Take A Rocketship To Space" is playing at the party Brick and Savannah infiltrate. Also, Dakota and Cavendish repeat a similar discussion Phineas and Ferb had in "Summer Belongs To You!" about flooding the engine.
In "Star Struck", the film crew member holding the boom mic and helping the director has a hat promoting the Nostrils, a soccer team from England that appear in the Phineas and Ferb episode "My Fair Goalie".
In "Love Toboggan", the song "Boat of Romance" from the Phineas and Ferb episode "That Sinking Feeling" is parodied by "Toboggan of Love", which is sung by Milo himself while on a toboggan with Melissa, Zack, Sara, and Neal being pushed by a comic store's boiler.
Near the end of "The Island of Lost Dakotas", Milo notes the shoelace fact that the plastic tip of a shoelace is called an aglet. In the Phineas and Ferb episode "Tip of the Day", Phineas and Ferb dedicate the entire day to the promotion of this invention. It would seem that Milo was not within the city limits during that episode; otherwise, he would have forgotten the fact along with everyone else.
In "Fungus Among Us", Cavendish and Dakota again argue about flooding their engine, like in "Summer Belongs To You!". At the end of the episode, Milo and his surviving friends find Heinz Doofenshmirtz, believing he will be the one to invent time travel.
In "Milo Murphy's Halloween Scream-A-Torium!", after Dakota's costumes land on Savannah, she emerges from the snow as the greasy-haired girl from The Grievance, a horror movie series that appears in Phineas and Ferb. Dakota and Cavendish dress up as Phineas and Ferb respectively during the song "The Last Halloween". One kid dresses up as Perry the Platypus and some others return in the costumes they wore to the sci-fi and fantasy convention in "Nerds of a Feather".
In "A Christmas Peril", during the Bureau of Time Travel's Christmas Party in 2175, the song "S'Winter" from the Phineas and Ferb episode "S'Winter" was playing. An instrumental version of "Candace Party" is heard as Nate tries to recover his luggage. In the future mall in 2195, Santa Claus made an appearance in a giant snow-globe. One of the sailors who appear in the episode is the same as a sailor who appeared in "Summer Belongs To You" when Phineas and the gang were heading back to Danville on their baguette boat.
Heinz Doofenshmirtz becomes a major recurring character in season two.
"The Phineas and Ferb Effect" is a major crossover event between Milo Murphy's Law and Phineas and Ferb. Many characters from which play major roles. Characters include Heinz Doofenshmirtz, Baljeet, Buford, Perry the Platypus, Major Monogram, Candace, Phineas, Ferb, Isabella and her Fireside Girls troop, Irving, and Linda and Lawrence Flynn-Fletcher. As Doofenshmirtz looks for the 24 Hr Periodic Table Channel he skips past scenes from the "Ferb TV" shows: The Klimpaloon and Giant Floating Baby Head Hour, Katt Karr, and Dancing with the Bears (featuring Vance Ward). There are also scenes from the Ducky Momo Theme Song and Horse in a Bookcase. Time Juice is said to be next to Pizzazium Infinionite on the Periodic Table. The container Doofenshmirtz pours the time juice into is the same as the component Candace takes when Phineas and Ferb are repairing the time machine in "It's About Time!". Candace is playing a Ducky Momo game when she first appears. During the construction montage scenes the Quirky Worky Song plays. The Giant Floating Baby Head makes an appearance and is M.U.L.C.H.ed. Milo hands Phineas a blow torch and some peanut butter, referencing when Phineas says they need those items in "Rollercoaster". Phineas mentions that Doofenshmirtz is Vanessa's dad. Professor Time's time machine looks similar to Professor Onassis' time machine.
The majority of "Agee Ientee Diogee" is set during the summer Phineas and Ferb is set. It shows some activities of the O.W.C.A., a secret organisation with animal agents that fight evil scientists. Along with Major Monogram, Carl the intern appears. Agent P's lair is shown. Doofenshmirtz has a cat named Mr Fluffypants II, a reference to a cat that Doofenshmirtz temporarily adopts and calls Mr Fluffypants in the episode "Spa Day", though the cat's actual name was Mr Cat.
In "Game Night" the dimension of the Spaghetti people is the same as the dimension a number of giant floating baby heads were seen in Phineas and Ferb The Movie: Across the 2nd Dimension.
In "Cake 'Splosion", Rain and Storm are said to be from Badgertown, a neighbouring city to Danville that was mentioned in "It's a Mud, Mud, Mud, Mud World" and appears in "Der Kinderlumper". It is revealed that Middletown, home of Middletown Middle School, is also in the Tri-State Area. The show Horse in a Bookcase is seen when Recurring Raccoon dunks the tv remote.
In "Disco Do-Over", when the Murphy's are practicing and when arrive at the roller skate rink they are dancing to Disco Miniature Golfing Queen. A lawn gnome is revealed to have been made in Drusselstein, the country Doofenshmirtz is from. Doofenshmirtz's first and one of his most revisited backstories was the story of how his family lost their lawn gnome. Doofenshmirtz mentions getting a bee stuck in his pants, this may be a reference to one of the times he was attacked by bees in "Skiddley Whiffers". Doofenshmirtz's college video of him skating into a toilet is seen again, which went viral in "Tip of the Day". An instrumental of Dance Baby is played in the background when Martin and Brigette meet Pete and Tina.
In "The Ticking Clock", Doofenshmirtz is singing Horse in a Bookcase when he first appears. Victor Verliezer interrupts the 28th annual substitute teachers conference, the previous 27th meeting was held in "Phineas and Ferb Summer Belongs to You!" (despite not being a full year between the two). Everyone attending is the same except one teacher was replaced with Ms. Baxter.
In "Milo's Shadow", Dr D brings up that he was raised by Ocelots, something first revealed in "The Chronicles of Meap". Dr D mentions the time a tinfoil ball took off his roof, which was what happened in "Rollercoaster". The Konsortium Of Otherworldly Knowledge Seekers holds their meeting at the Danville Community Center.
In "Freefall", the bird runs into the sixth safety system of the wind turbine.
In "Milo's World", Josh is reading a Ducky Momo comic. In his bag of holdings, Milo the Great has a blow torch and some peanut butter. While Captain Chaos is causing havoc, the Beak's theme plays from "The Beak".
In "Abducting Murphy's Law", as Melissa and Zack wait for Milo the music from Watchin' and Waitin' plays, a song from "Don't Even Blink". It sounds like Zack was hit by something similar to the inside-out-inator that Doofenshmirtz is seen to get hit by in "Phineas' Birthday Clip-O-Rama!"
In "The Goulash Legacy", Doofenshmirtz sings the start of the song from "Moon Farm". Doofenshmirtz invented the chicken-replace-inator in "What A Croc!" to embarrass his brother. There is a section of Doof's Eat-it-all-inator from "Knot My Problem" among the portable inators. The song Goulash is preformed by Love Händel.
In "Adventure Buddies", Vanessa, Heinz Doofenshmirtz's daughter, makes an appearance. When Doofenshmirtz looks at the card Perry sent him an instrumental of When We Didn't Get Along plays, a song from "It's About Time!". When Doofenshmirtz realises that Scott could be his new adventure buddy the sting from when Phineas realises what he's going to do today plays.
In "Look At This Ship", Zack guesses correctly that the thing from that one movie with that guy is the otherdimensionator from that movie "Across the 2nd Dimension", with "that guy" perhaps referring to it's creator, Doofenshmirtz. Dakota and Doofenshmirtz eat at Mr. Slushy Dawg.
In "First Impressions", Milo and a number of his colleges are shown to have gone to John P. Trystate Elementary, the same elementary school that Phineas and Ferb currently attend, as seen in "Doof 101".
In "Escape", Milo gets stuck in an elevator in the Googolplex Mall, a common location seen in Phineas and Ferb. As Nolan pulls the cowboy figure across the floor, a girl can be seen with a recoloured Mary McGuffin doll, the titular plot device of "Finding Mary McGuffin".