History ThrowItIn / WesternAnimation

** Homer's famous "D'oh!" was improvised by Castellaneta. The script only said "annoyed grunt." (And still does.) It was originally a Creator/LaurelAndHardy reference (Oliver Hardy would occasionally let out a pained "D'ooooooooooh"), but Castellaneta was told to shorten it the first time he used it.

* ''WesternAnimation/{{Futurama}}'': An InUniverse example is where Calculon is showing a clip of a new episode of his show where he does a BigNo. He informs the talk show host he was actually supposed to say "yes" but kept it in.

* ''WesternAnimation/{{Futurama}}'': An InUniverse example is where Calculon is showing the clip to a new episode of his show where he does a BigNo. He informs the talk show host he was actually supposed to say "yes" but kept it in.

** Recurring guest star Creator/AlbertBrooks is known for doing this. Noticeable when he plays Hank Scorpio in "You Move Only Twice" - most of his fast, random declarations are improvised. The entire Hammock district routine is improvised - hence why Homer only replies with a quick "Yes" because even Creator/DanCastellaneta had trouble keeping up with Brooks. Only at the end does he catch up and reply, "Oh, in the hammock district".

* In the ''WesternAnimation/SouthPark'' episode "South Park is Gay!," the [[spoiler:Crab People]] were originally just a placeholder Creator/TreyParkerAndMattStone were using until they figured out the ''actual'' plot for act three, but then just ran with it when they couldn't come up with anything else. For what it's worth, later episodes have used "[[spoiler:Crab People]]" as a stand-in for [[TakeThatUs a really stupid idea]].

** Also, the famous [[EnsembleDarkhorse Foamy Mouth Guy]] was just going to faint in the background. Then an animator got ''really'' creative...

** Not to mention that the show's staple MixAndMatchCritters were also the result of a particularly bored animator.

** The reason "Reef Blower" ended up becoming a NoDialogueEpisode was due to the sound equipment being damaged in production.

* ''WesternAnimation/LooneyTunes''. Creator/BobClampett's 1943 short ''WesternAnimation/AnItchInTime'' has a scene of a dog, having been irritated by a flea, scooting wildly around a carpet on its rear end. As an "inside" joke, Clampett and his animators added an off-color gag of the dog pausing to tell the audience, [[ADateWithRosiePalms "Hey, I'd better cut this out, I may get to like it!"]] fully expecting that either the studio or the [[UsefulNotes/TheHaysCode Hays Office]] would have it removed. Astonishingly, [[SurprisinglyLenientCensor they didn't.]]

** The creators accidentally [[OneSteveLimit gave two characters the last name "Wiggum":]] the town's [[PoliceAreUseless idiotic police chief]] and one of Lisa's [[TheDitz unintelligent classmates.]] Actually, they're both dumb and kind of chubby...okay, they're father and son now.

* In ''WesternAnimation/BatmanTheAnimatedSeries'', [[https://www.youtube.com/watch?v=Ni1EaVcO_1M#t=02m42s The Joker's squee]] after explaining his plan to Batman in the episode "[[Recap/BatmanTheAnimatedSeriesE41JokersWild Joker's Wild]]" wasn't in the script. Creator/MarkHamill just sort of did it after reading his line, and the cast and crew were laughing so hard that they apparently took the rest of the day off. The next day, they went ahead and added an extra second of animation to include it.

* In the ''WesternAnimation/YoungJustice'' episode "War", Robin and Impulse's fistbump was thrown in by the storyboard artist, who was a fan of [[MythologyGag their friendship in the comics]].

* ''WesternAnimation/RegularShow''[='=]s signature use of real-life (but predominantly '80s) music came as the result of a misunderstanding. During the storyboard animatic process in the early days, the creators threw in music they listened to as kids as an inside joke, reminiscing on the decade that inspired ''Regular Show''[='=]s overall style. When the animatics were presented to Cartoon Network, they weren't aware of the inside joke, and asked the creators if they wanted to see if CN could get them a license to use said songs in the show, to which they accepted in hilarious bewilderment.

** Homer's famous "D'oh!" was improvised by Castellaneta. The script only said "annoyed grunt." (And still does.)

* ''WesternAnimation/RegularShow'''s signature use of real-life (but predominantly '80s) music came as the result of a misunderstanding. During the storyboard animatic process in the early days, the creators threw in music they listened to as kids as an inside joke, reminiscing on the decade that inspired ''Regular Show'''s overall style. When the animatics were presented to Cartoon Network, they weren't aware of the inside joke, and asked the creators if they wanted to see if CN could get them a license to use said songs in the show, to which they accepted in hilarious bewilderment.

* The first Greek AlternativeForeignThemeSong of ''WesternAnimation/InspectorGadget'' was [[https://www.retrojunk.com/content/child/intro/page/3972/inspector-gadget/2#/content/child/intro/8136/show this]]. Towards the end, you can hear some of the vocalists bursting into laughter and ad-libbing. This was left in the final recording.

* One of Sonic's lines in ''WesternAnimation/SonicBoom'' is quite obviously Creator/RogerCraigSmith flubbing his line but [[http://ghostanjo.tumblr.com/post/164662618389 rolling with it]].
-->'''Sonic:''' Use this to build a- a bigger bag- baggit bo- build a begger- built it ba- buggy baggit- bagger box buzzard... ''(shakes head)'' The answer is simple, but saying it not so much.

** Creator/HumbertoVelez, Homer's original Latin Spanish voice actor, came up with the dub's translation of the "Sweet Merciful Crap!" line in "Summer of 4 Ft. 2", being "Me quiero volver chango", a phrase a friend would often say.

** '''''[[MeanwhileBackAtThe MEANWHILE!!]]'''''

* Megatron's famous "''[[VerbalTic Yeeeeeeeessss...]]''" from ''WesternAnimation/BeastWars'' wasn't originally scripted, but was improvised by voice actor Creator/DavidKaye, who thought it fit the character. It did, and quickly became his CatchPhrase.

'''Stan:''' That's not ''in'' the script They do this all the time.\\

** InUniverse example: In "A Very Crappy Christmas," the boys are making a Christmas film. It was originally supposed to be wholesome, but naturally, [[HotBlooded Kyle]] and [[PolitcallyIncorrectVillain Cartman]] got into a fight while recording and started screaming profanity at each other.
-->'''Sound man:''' The script. It's sweet.\\

** InUniverse example: In "A Very Crappy Christmas," the boys are making a Christmas film. It was originally supposed to be wholesome, but naturally, [[HotBlooded Kyle]] and [[PolitcallyIncorrectVillain Cartman]] got into a fight while recording and started screaming profanity at each other. The sound guy thought it was hilarious and intentional, so the boys altered the script.