'''Airdate:''' September 27, 2009

When Stewie enters a genetically engineered pig at the carnival, Brian asks him where it came from. Stewie reveals to Brian that with an interdimensional teleporter, he can travel to different universes and takes Brian to a universe without religion, where everything is 1,000 years advanced. After exploring that universe, Brian asks if Stewie can take him to other universes and he agrees. First, they stop at a ''Flintstones''-esque universe, followed by a universe where America never bombed Japan in World War II, making the world dominated by Japan. Later, they travel to a universe where everyone has two heads, one happy and one sad, followed by a universe where they are trapped in a second Ice Age, where Brian helps them escape.

After going to a universe where "everyone has to poop right just now", they go into a universe where everything is run by {{Disney}}. They're happy with staying there until the inhabitants attack Mort the Jew. They then go to a ''RobotChicken'' universe, followed by a universe where the U.S. botched the Cuban Missile Crisis and the world is in World War III, then a universe with everyone animated poorly. The universe traveling continues with stops at universes of fire hydrants, homosexuals, live-action, political cartoons, a guy who yells compliments from afar and misleading portraiture. They finally stop at a universe where the roles of dogs and humans are reversed. Brian wants to stay to Stewie's chagrin and a fight for the traveling remote causes them to drop it and break, leaving them with no way back home.

In the dog universe, they decide to go the Griffin house, with dog versions of the family and a human version of Brian. The two hide after Stewie bites Dog!Peter and "human control" is called upon. Dog!Stewie gives them his traveling remote, but wanting to live in a man-dominated world, Human!Brian stows away with them. This time, they make it back home and Human!Brian wishes Stewie and Brian goodbye before getting run over.

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!!"Road to the Multiverse" contains examples of ([[YMMV/FamilyGuyS8E1RoadToTheMultiverse YMMV goes here]]):

* AlternateHistory: Some of the universes, like the Japan-dominated universe and the World War III universe.
* AlternateUniverse
* AnimationBump: The Disney sequence.
* ArtShift: Many, from the Disney-esque animation to stop-motion and even into live-action.
* ArtisticLicenseReligion: The Sistine Chapel still exists in the universe with no religion.
* AuthorTract: Without religion, the world is advanced by 1,000 years. It's not as bad as the entirety of "Not All Dogs Go to Heaven" or even the end of "I Dream of Jesus" where Jesus Himself tells Peter that all religion is crap (with Brian yelling, "''Thank'' you!") in terms of religion-bashing, but it will leave a bad taste in some viewers' mouths.
* BrickJoke: Stewie removes Brian's poop in the futuristic universe and tells him it goes to another universe. Later, when the two are trapped in an iceberg, Stewie notices the poop.
* ButtMonkey: Meg. Even in the futuristic alternate universe, where she's smoking hot, she's still considered ugly compared to Lois (who is so hot, to quote Stewie, "...you'd have to put your penis in a wheelchair." On DVD, the line is, "...your penis would shoot right off your body.") Of note, and probably obvious to many, this universe's Lois doesn't appear.
* {{Disneyesque}}: The Disneyverse. This episode provides the page image.
* ElementalPlane: The episode featured quite a few of these.
* LookBothWays: At the end of the episode, Human!Brian promptly gets hit by a car as he crosses the street.
* MotorMouth
-->'''Dog!Peter:''' OH-MY-GOD-I-KNOW-THAT-SOUND-IT-MEANS-THERE'S-A-POTENTIAL-INTRUDER-AT-THE-FRONT-DOOR-OR-ONE-OF-MY-PALS-EITHER-WAY-I'M-EXCITED-AND-READY-FOR-ANYTHING!
* NoodleIncident: Appearently, Dog Stewie and Human Brian have had a universe-hopping experience of their own.
* PetHomosexual: Parodied. Chris wins a "live, genuine homosexual" as a carnival prize.
* RockThemeNaming: Parodied in the Flintstone universe with Rock-Peter and Rock-Lois.
* ShoutOut
** One universe is based on ''TheFlintstones'' (which, coincidentally, was the next cartoon SethMacFarlane worked on before he put it on hold. Now that ''The Cleveland Show'' has been canceled and ''AmericanDad'' will move to TBS, [=MacFarlane=] may work on the show, but nothing's set in stone).
** [[PlanetOfTheApes "Take your stinkin' paws off me, you damn dirty dog!"]]
** Brian's alternate name in the dog universe is [[{{Dynasty}} Blake Carrington]].
** [[QuantumLeap "I hope this next leap will be the leap home."]]
* {{SMURFING}}: Exaggerated in the Flintstone universe.
-->'''Brian:''' Wanna get the rock out of here?
-->'''Stewie:''' Rock yeah.
* StealthPun: In the Disneyverse, Joe appears as [[Disney/BeautyAndTheBeast a teapot]]. So he's "a cup of Joe".
* TakeThat
** At Creator/SethGreen and ''RobotChicken''.
-->'''Stewie:''' How does it feel like to be on [[{{Creator/Fox}} a major network]] for 30 seconds?
-->'''Chris:''' FUCK YOU!!!
** The punchline of the Disney universe (where everyone beats the crap out of Mort) reflects rumors of Walt Disney's alleged Antisemitism.
* WhatMeasureIsANonHuman and DudeNotFunny: In the World War III universe, Lee Harvey Oswald shot Mayor [=McCheese=], with Jackie Kennedy eating the scattered head.
-->'''Brian:''' That joke's not in bad taste, right?
-->'''Stewie:''' Who cares? He's a cheeseburger.