Then there's Talos from Greek mythology, the original model for Dungeons & Dragons' "iron golem".
Myths are replete with this. Hittite mythology has one. Golden automata and other mechanical creatures were all over Greek Mythology. Rabbi Loew's Golem was well-known for being large and powerful. Creating a mechanical man is a very old idea indeed, and making it huge is simply the next step up. Naturally, it's arguable which of these "count" as actual mecha, but the basic idea goes back.
The DVD subtitles, at least, give "MIMICS THREE STOOGES" or "IMITATES CURLY FROM THE THREE STOOGES" rather than "WHOOP WHOOP WHOOP".
The triangular Cool Shades worn by Soundwave and Prowl of Transformers Animated are often mistaken to be a Shout-Out to the famous ones worn by Kamina of Tengen Toppa Gurren Lagann, but Derrick J. Wyatt said they were actually a reference to the much older ABC Warriors of 2000 AD fame. They were also worn by several other characters before Kamina, including Calvin (in one strip) and Ash's Squirtle. Many also thought the Lagann had some influence on the Headmaster design (both are robots that could become the head of another mecha to boost its power). However, besides the idea of a robot becoming a Transformer's head dating back to G1, Wyatt stated that he'd never seen Gurren Lagann until after the first season was already done with production (though he stated that if he had seen it before, the design would probably have stubby legs and let Masterson poke his head out the top).
Although many people think the catcall "Hellooooo, nurse!" was originally from Animaniacs, it originated several decades ago, in vaudeville.
Such as Wakko's accent, which was based entirely off Ringo Starr.
The cars in this short bear a certain striking similarity to Cars. Thing is though, the short is actually from 1952!
Woody Woodpecker's first appearance was actually as the villain of a short of a now forgotten character called "Andy Panda". Oh, and his laugh (produced by Mel Blanc) didnt start with him either. Blanc used it earlier in a few of his Warner Bros. shorts like Porky's Hare Hunt.
When The Simpsons first aired, some viewers believed certain lines popularized by Bart to have been invented by the show's creators. These include Bart's replacing the words of "Jingle Bells" ("... Batman smells, Robin laid an egg...") in the first episode and "Eat my shorts", first said in The Breakfast Club (1985). And while "Yo!" quite obviously predates Bart Simpson, being famously used at the ending of the first Rocky movie (1976), many Generation-Y kids grew up not knowing that.
This is particularly ironic, as the creators note in the first season's DVD commentary, because Bart was meant as social commentary, speaking almost entirely in borrowed catch phrases and clichés. When the popularity of The Simpsons caused people to attribute the phrases to Bart instead, the joke was lost on many viewers. In fact Nancy Cartwright, the voice of Bart, says that she first heard "eat my shorts" when she was in high school (in the 1970s), and that it became a running gag among the fellow members of her high school marching band.
Homer's iconic "D'oh!" outburst is from Laurel and Hardy (though in a shorter form), as confirmed by Matt Groening.
While Homer is named after creator Matt Groening's father, he also shares his name with a supporting character in Nathanael West's novella The Day of the Locust, which was written in 1939. This has amused more than a few English majors.
Many famous Simpsons episodes are direct homages to or parodies of other material, especially anything in the Halloween episodes.
Ah, Toy Story! What a cute and creative idea, the thought that toys actually come alive while their master is away. Older folks remember reading those stories when they were about good old Raggedy Ann.
The Velveteen Rabbit was slightly younger — 1922 to Raggedy Ann's... call it 1918 — but the doll predates the stories by a couple years. Seems older, what with the scarlet fever, and all.
Read When Toys Come Alive by Lois Rostow Kuznets. She has the whole history.
The Princess and the Frog, featuring Disney's first black princess, has already been accused of trying to cash in on the Obama presidency. Anyone who follows Disney will remember this was on the drawing board years before Obama was nationally known, and the first teaser trailer was available before the Democratic primaries.
The American Darkstalkers cartoon featured a bespectacled boy named Harry Grimoire who was studying magic (and happened to have Felicia as a "pet"). This would've been an obvious rip of Harry Potter, if not for the fact that the cartoon came out some years before.
A similar thing happened with The Books of Magic, which has a bespectacled young boy who is destined to be a wizard — in fact Neil Gaiman admits that despite having a bespectacled wizard go to school wasn't his original idea, and that he and Rowling were more inspired by Arthurian legends than each other (unfortunately, a magazine Mis-blamed him as having accused Rowling of ripping off his ideas, which he rebutted).
Most Disney fans assume that Mickey Mouse is Disney's first cartoon character, and Peg-Leg Pete was created to be his primary enemy. Actually, Pete was the very first recurring Disney character, created in 1925 (before even Oswald the Lucky Rabbit) for one of Disney's Alice Comedies, a series of shorts which mixed live action and animation. Pete was always a villain, but the fact is that he was imported into the earliest Mickey cartoons to give Mickey an established character to fight, not the other way around.
For that matter, most people don't know that Mickey was an Expy of Oswald...but even fewer know that Oswald himself was an Expy of Felix the Cat.
Pete's son, PJ, is generally thought to have been created in 1992 for Goof Troop. He was actually created half a century prior, debuting in a Donald Duckcartoon called "Bellboy Donald" (though he went by Junior and he looked like Mickey Mouse with cat ears), and the character is only 17 years newer than his father. However, his personality was the exact opposite in every way from what was to come, so he simultaneously looked less like his father and acted (and sounded) more like him.
Likewise, Goofy's son, Max, was created as "Goofy Jr." in 1951 in the Goofy short "Fathers Are People", but also had extensive changes done to his personality and design. Though the personality changes weren't as extreme as PJ's (Max kept his wild side, he just gained a serious side too), the appearance changes were more extreme (originally "Goofy Jr." was a redhead with a pink nose and no ears).
There used to be a very vocal faction at the IMDb forums which reckoned that "all of DreamWorks' ideas were stolen from Pixar" (yes, all of them). At least two of their favorite examples were shown to be nonsense, as they were in production years before and only bore a superficial resemblance, and in any case one of them (Flushed Away) was actually an Aardman Animations movie — the DreamWorks involvement was minimal.
Spoofed in the "Springfield Shopper" booklet that comes with the Simpsons Movie DVD; in it, Homer (as a movie critic who's way behind with his column) describes Star Wars (by which he means A New Hope) as being "a parody of Spaceballs".
To this day, there are still fans of the Teen Titans cartoon who are surprised when they find out the cartoon was preceded by the Teen Titans comic book by 41 years.
In one episode of Recess, Gus is involved in a plot against the Ashleys wherein he claims Ashley is also his name - insisting that it's not that unusual in the progressive 1990s. In reality, "Ashley" was almost solely a boy's name until the early 20th century; it was perfectly acceptable for a boy to be named Ashley over a hundred years before the episode was written or aired.
One of the best known examples in pop culture would be Ashley Wilkes of Gone with the Wind, a film consistantly put in top 10 lists.
You know that routine on A Pup Named Scooby-Doo that Shaggy and Scooby-Doo had. Shaggy makes an Incredibly Lame Pun. Scooby-Doo laughs, then says, "I don't get it." It comes from Hang in There, Scooby-Doo on The Scooby-Doo/Dynomutt Show. The gang had found a cassette of rock music in the cavern.
Shaggy: Those cave teenagers love their rock music?
Scooby-Doo: (laughs) I don't get it.
On a larger scale, a lot of baby boomers who grew up in The Sixties, if they have no knowledge of animation history, will be surprised when you tell them that cartoons from The Golden Age of Animation such as Looney Tunes and Tom and Jerry were coming out in the 1930s and '40s, and were already decades old back when they remember watching the cartoons on Saturday mornings.
The expression "Cowabunga!" did NOT originate on Teenage Mutant Ninja Turtles (or even the surfer/skater culture they were imitating). The phrase originated from "The Howdy Doody Show" (1947-60), spoken by Chief Thunderthud, the Indian founder of Doodyville.
Judging from its sheer presence on the internet, it's a fair assumption that the My Little Pony franchise never caught on with males until My Little Pony: Friendship Is Magic, but there were bronies (not that they called themselves that) back as far as Generation 1 - believe it or not, the G1 cartoon series usually dealt with boy-friendly epic fantasy adventures, not stereotypically girly fare. But since 4Chan wasn't around in The Eighties, the male fans of the show didn't make themselves known as a significant Periphery Demographic until the latest series.
The infamous "Rainbow Dash always dresses in style" quote is usually associated with G3.5 (as is the theme song the lyric appears in), but the quote - and the song - were actually borrowed from G3.
Actually, who here remembers the first time we saw multi-colored equines dancing across the screen in Western Animation. You know, small unicorns dancing around, and pegasi too. What, The Eighties? No...we saw these as early as The Forties - I'm talking about the Pastoral in Fantasia.
The whole "Adult men enjoying a show for girls? It's the end times/turning point for masculinity/insert flimsy sociological viewpoint here" makes you wonder if everyone has forgotten Sailor Moon was originally for a similar demographic.
Similarly, Friendship is Magic is hardly the first time a Merchandise-Driven franchise targeted solely towards little girls was adapted into a story-driven animated series with only superficial girly elements that could be (and was) enjoyed by both genders. She-Ra: Princess of Power beat it to that honour in 1985.
Remember that one episode of Family Guy where Peter sang "Surfin' Bird"? Turns out the idea of using that song in a cartoon has been done before — a cover was used for the short-lived CBS cartoon Birdz.
Family Guy causes a honking crapload of these sorts of errors thanks to its Reference Overdosed nature. Any film or TV show clip later parodied on FG will have hundreds of comments on YouTube mistakenly asserting the video is a reference to Family Guy, even if the age of the clip makes it obvious that it originated decades before Seth MacFarlane was even born.
The "Do you remember [X]? Pepperidge Farm remembers." joke from the episode "Hell Comes to Quahog" had also been done in the Futurama episode "A Fishful of Dollars" seven years earlier, which made many say They Copied It, So It Sucks.
Pop quiz: what was the first animated series about a teenager from a primitive society who is granted a magical weapon that, when he holds it above his head, grants him super-strength and transforms his pet into a fierce animal sidekick, and it features a character named She-Ra? If you guessed He-Man and the Masters of the Universe (1983), you're wrong - that honour goes to Hanna-Barbera's The Mighty Mightor, created in 1967.
A lot of Internet commentators accused the Gravity Falls short "Hidebehind" of ripping off the Slender Man Mythos— being apparently unaware that the Hidebehind is a much older folkloric creature.