Omi from Xiaolin Showdown and Xiaolin Chronicles. There are multiple moments where Omi says something, and the cast, sometimes including the villain, stops whatever they were doing and try to figure out what the heck Omi just said. And in one episode, Raimundo suggests that the lesson for the day is "Omi can't use slang."
Omi: He who is last to laughing, laughs most loudly! Raimundo: What Omi just did to that sentence is what we're going to do to you!
Early: Where do I see myself in five beers? Sheriff: No, "years", "years"! Early: Uh, I dunno. Jail?
Dan Halen: Lets talk briefly about your work ethic Early: Well, I don't think ethnics do no work. I mean, that's they problem, really. If you ain't like me, go hang from a damn tree.
All the babies in Rugrats do this, even the more mature Angelica. Most of the babies' internal logic in this show was based on malapropisms and the sheer willingness of everyone else to believe they were telling the truth. Occasionally subverted, though, as sometimes Angelica says a malapropism and the babies repeat back the right word.
Jim Moralès from Code Lyoko. Sissi delves into this too.
Aelita did it a couple of times during the time following her being brought into the real world. One memorable one was when she told Jeremie that he was "as stubborn as a fool" during an argument about her DJing the school dance. He corrects her, saying "It's stubborn as a mule!" but hers does make some sense.
Total Drama's Lindsay does this mainly with names ("Kyle" for Chris, "Doug" for Duncan, and so on) and occasionally with other words (e.g. "dental" for "mental") as one of the most high-profile elements of her Dumb Blonde stereotype. Beth also got into the act when she first arrived on the island and told Chris, "It's so incredulous to meet you!"
"It's about time for me to employ a little stragedy." (Bunny Hugged)
"Bon voyagey!" (any cartoon with a simulated sail-off)
"Like the Romans say, E Pluribus Uranium! (Roman Legion Hare)
"I am a little fat-i-gyoo-d" ("Transylvania 6-5000")
in another short, he says that a bullet must have "ricoshateted"
Red Hot Ryder, the dimbulb from Buckaroo Bugs, doesn't so much deliver a malapropism as it is a non-sequitur:
Bugs: (holding a carrot like a gun against Ryder's butt) Stick 'em up! Or I'll blow your brains out! Ryder: Well, that's mighty neighborly of ya!
In "French Rarebit," Bugs tours Paris to see the "mon-sewers and madam weasels."
In Falling Hare, he learns that:
"The constant menace to pilots are the gremlins who wreck planes with their 'dia-bo-LI-cal saba-tagey'".
In Ali Baba Bunny, the thug guarding the treasure of Ali Baba is prone to this, repeatedly botching the phrase "Open Sesame" to enter the magic cave:
"Uh, Open Sasparilla? Open Saskatchewan? Open Septuagenarian? Open Saddlesoap?"
Arch from the 1946 Sniffles cartoon "Hush My Mouse", who was a cartoon version of Ed Gardner's character Archie from the radio show Duffy's Tavern ("Well, if it ain't Eddie G. Robincat in the flesh and fantasy!")
In another, Sniffles mispronounces "etc." (et cetera) in one scene, or rather, he pronounces it exactly as it appears.
Porky the Wrestler grappler Hugo Bernowskiwoskimowskiskowski:
Hugo: I fight anybody my heavy!
In "Lighthouse Mouse," a parrot repeats what Sylvester says, prompting Sylvester to retort "You said what I heard me!"
In "Zip Zip Hooray" (an edited segment of the pilot The Adventures of the Road Runner), Ralph Phillips says he wants to be a "p-sychoanimalist" when he grows up.
In one episode, the Eds play a game of Truth or Dare and end up acting like one of the other Eds. Eddy ends up acting like Edd and tries to make himself sound smarter by using large words. Of course, since his vocabulary isn't as good as the real Edd's, he ends up making a lot of malapropisms.
In the episode "Boogie Frights", Blossom misquotes Benjamin Franklin's proverb "Early to bed and early to rise makes a man healthy, wealthy, and wise":
Blossom: Now, girls, you know we need to get plenty of sleep. It’s our responsibility as superheroines to be well-rested so that we’ll be at peak crime-fighting performance whenever evil rears its ugly head.
And, like Ben Franklin always said— “Early to bed, early to wake, makes a lady smart, pretty, and great.”
The episode "Telephonies" has the Gangreen Gang in the Mayor's office making prank phone calls at the cost of the dignity of Mojo Jojo, Fuzzy Lumpkins, and Him until they've had enough and call the Mayor for action:
Big Billy: Hullo? Him: Let me speak with the Mayor! Big Billy: Uh, he's not in right now. Can I take a massage?
On Animaniacs, Wakko Warner was prone to these. He once shouted at a man whom he thought was a magician to "pull a rabbit out of your pants!" (Then again, Wakko was also a Cloudcuckoolander, so according to his thought processes, that might not even count as a mistake.) He and siblings also mispronounce longer words like skulecatary for secretary and "p-sychiatrist" for psychiatrist.
Sam: Now make sure you don't leave that candle unattended. Mrs Price: Of course, I'm very reprehensible.
King Julien, The Ditz of The Penguins of Madagascar, doesn't exactly use the wrong words, but he's prone to mangling the actual form of the words. "No, I will not succeed. No one will be sucking seed!"
Tish's mom from The Weekenders like for instance "fishing model" instead of fashion model, leading to her Catchphrase of "Is what I say" any time this is pointed out to her and/or Tish translates for her.
Don Karnage of TaleSpin is notorious for mangling the English language.
In early episodes the kids had trouble pronouncing long words, like hermaphrodite.
Also, in Officer Barbrady's debut in "Chickenlover", when admitting that he can't read, he exclaims "I'm illegitimate!"
In "Sexual Harassment Panda" Craig refuses to answer Mr. Garrison's question on the grounds that it may "incinerate" him before Mr. Broflovski tells him the correct word.
In “The Cissy,” Cartman claims to be “Transginger” so that he doesn’t have to use the same restroom as the “Cisgingers.”
Goof Troop. Goofy and Pete are both habitual Malapropers. Goofy would typically use real words that were the wrong word ("decimated driver", "you're historical"), but Pete would do a mix of that, mixing two words together, and giving an incomprehensible phrase such as "Do as I think not mean what I say." To hilarious effect in the second episode, when their sons emulated their fathers' behavior so that they would be allowed to be friends, PJ (who is typically rather eloquent) incorporated the malapropisms. Pistol did this in at least one episode, when she mentioned Amelia "Airhead" as an example of girls who can fly.
In the House of Mouse short "How To Be a Gentleman", this happens to Goofy as his botched attempts to greet the Queen of England result in numerous blows to his head from her scepter.
Narrator: One should bow gracefully and say, "my dear Queen, how delightful to make your acquaintance". Goofy: My queer dean, how delightful to acquaint your maintenance. (the queen bashes him on the head so hard that he falls and a lump grows on his head...followed by several more lumps growing from said lump)
From the Popeye cartoon "The Natural Thing To Do":
Olive: Er... let's converse. Bluto: Hey! I hear conversing is comin' back! Popeye: Yeah. And convoisin' breaks up the monopoly of not talkin'!
In Goonland Popeye finds his imprisioned Pappy, who doesn't want anything to do with him. Through his tears Popeye moans "Ohh, he don't know his own skin an' bones!"
"Service With a Guile" has Popeye and Bluto fighting over who will service a Navy admiral's car at Olive's service station. Olive says to let Popeye do it because "he's more mechanically reclined."
At the end of the Mike, Lu & Og episode "Giant Steps", Mike is told the truth about the "giant" that's coming to the island.
Wendell: It's a metabolical statement. Og: Metaphorical. Wendell: Yeah, that too.
In The New Scooby-Doo Movies episode "The Caped Crusader Caper", Professor Flaky often mixes up sayings.
Professor Flaky: I like Shaggy because he's dumb to kind animals. The Penguin: That's kind to dumb animals! Dumb, dumb, dumb!
Mr. Whiskers: I'm no fighter, I'm a pacifier! [cut to a live-action shot of a baby sucking on a pacifier shaped like Whiskers's head] Mr. Whiskers: You know what I mean.
On Wild Animal Baby Explorers, Sammy the Skunk is this, but only because he's younger than the other characters and therefore is still learning the right words.
Skip: We are a looking at a hippopotamus. Sammy: Hippo... bottomus? Hipsomonoplus? Skip: We can also just say "hippo."
Arthur: D.W. does this every now and then and is always immediately corrected by Arthur. Justified in that she is four years old. For example, in "Feeling Flush", she confuses "water conservation" for "water conversation".
Kaeloo: Stumpy, Smileyland's resident idiot, does this quite frequently. For example, he refers to a library as a "liblerary", and thinks Mr. Cat is "intelligious".
Joey Mousepad: What if management remains intragnisant* Likely trying to say "Intransigent", meaning "inflexible" or "uncompromising".? Donbot: From the context, it is clear what you mean.
Punky Brewster: "The Quartersize Quarterback" has Glomer making a forward pass of a football to Allen, to whom he has given the abilities of a pro player.
In Cow and Chicken, characters would sometimes confuse their words with similar-sounding ones.
In "The Cow with Four Eyes", Chicken replies to Cow telling him he needs a prescription in order to have glasses by saying "So I'll get a subscription".
In "Comet", Cow says "posterior" when she meant "posterity".
In "Cow's a Beauty", Cow says she'll win all the "beauty pigeons" instead of "pageants".
Buzz is this on Beat Bugs, sometimes. In "Let it Be," for example, she meets a firefly called Mother Mary that she calls her "cardigan angel."
In "Nancy vs Dudley" from Fancy Nancy, JoJo misconstrues the Eiffel Tower as the "Awful Tower." At first, Nancy is annoyed, but later after she realizes that she wants JoJo to play with her and asks what she wants to play, she quite happy to agree with JoJo's request: "Let's build the Awful Tower."
In the Ready Jet Go! episode "Every Day Is Earth Day”, Carrot mistakes "toaster" for "poster" and presents a toaster instead of a poster at the DSA celebration, much to Mr. Peterson's annoyance.
Tigger of the various Disney incarnations is a master malaproper.
Tigger: (regarding Rabbit) Well, you know ol' cotton-bottom. He's the self-deficient type. Ya' know, a real do-it-without-ya kinda guy.
In "Buster's Buried Treasure" on My Friends Tigger & Pooh, Lumpy repeatedly uses the phrase "gold balloon" in place of "gold doubloon."
Sol from Sons of Butcher is infamous for butchering quotes, giving such "wisdom" as "My father who does art in heaven", "Desperate times call for separate pleasures", "I'll welcome death with open legs", and "Take it sleazy!"
Season 1, Episode 4 of Bojack Horseman has three separate people butcher the idiom "Fool me once, shame on you; fool me twice, shame on me":
First Mr Peanutbutter:
Fool me once, shame on me. Fool me twice...fiddle-dee-dee.
Then Virgil van Cliff:
Fool me once, shame on you, but teach a man to fool me, and I'll be fooled for the rest of my life.
And finally, Todd:
Fool me once, fool me twice, fool me chicken soup with rice.
Danger Mouse: From "Public Enemy No. 1", where DM has amnesia and Baron Greenback makes him think he's a bandit called the White Shadow, Greenback learns that somebody has beaten him to crimes he was planning:
Stiletto: The White Mouse. Danger Shadow. You know... your life-long anniversary.
In "SpongeBob's Road to Christmas", after SpongeBob tells Plankton, "You just gotta believe," Patrick repeats, "You just gotta bleed."
In "Life of Crime", Patrick misspeaks "Liar, liar, pants on fire" as "Liar, liar, plants for hire." SpongeBob promptly corrects him.
Work It Out Wombats!: In "Special Delivery," Zeke says that Malik's drawn out route to Sammy's house looks like a long 'pasketti' noodle. And in "Zeke's Collection Selection", he keeps mispronouncing 'bonanza' as 'bananazana'.
Darla commits a malapropism in "The Case of the Puzzled Pals":
Alfalfa: I still can't figure out why Spanky would want your doll. Darla: If he were here, you could question him. But he must be on the ham. Buckwheat: That's lam, not ham. Darla: Oh. Sorry.
In "The Zero Hero", Alfalfa says in a defiant tone, "I'm half the man [Captain Muscles] is!"
One episode of The Boondocks features Dewey, a wannabe black power activist, greeting Huey with the phrase "salami, eggs, and bacon." He was going for the Arabic greeting "as-salaam alaikum." What's especially amusing about this is that Muslims don't eat salami or bacon because they don't eat pork, thus making Dewey look even more ignorant.
Klarion: Foolish mortal! Klarion is chaos personified! He cannot be constipated! Teekl: Meow. Klarion: Yeah, yeah, 'contained'. He knew I meant 'contained'.
The Beatles' "Eight Days A Week" was already cited in the Music tab; the cartoon episode extends it. When movie star Lips Lovelace loses his ability to kiss, Paul thinks it's absurd. "Anybody can kiss," he says.
Lips: Really? Eight days a week? Six weeks a month? Thirteen months a year?
In "Nitwit Neighborhood News", Patrick thinks a criminal (whom he mistakes for a celebrity) is wearing a Suspicious Ski Mask so "he won't be noticed by pepperoni!" He means "paparazzi", and Squidina corrects him.
In "Mid-Season Finale", Patrick reminds the audience to "stay turned" for his show.
In "Fun & Done!", Patrick pronounces "kazoo" as "Kalamazoo".
"Olly Olly Organ Free":
Patrick pronounces "segue" as "seg-yoo" instead of "segway".
When his stomach hurts, Patrick opts for "abominable" (abdominal) surgery.
In "The Star Games", Patrick mispronounces "the Cretaceous period" as "the crustacean period".
In "Super Stars", superhero Patrick gives a shout of "Up, down, and away!"
In "There Goes the Neighborhood", Patrick pronounces "varicose veins" as "very close veins".
In "Movie Stars", SpongeBob says "look no farther" and Patrick adds "and no mother!"
"Dr. Smart Science" has two:
When giving a lecture on the Zodiac, Patrick mislabels "Sagittarius" as "Saggy Terry".
After spending the entire episode being lectured against using pseudoscience, Patrick finally identifies it and calls out GrandPat for using it... except he pronounces it "strudel science". Sandy shrugs and says "eh, close enough."
"The Commode Episode":
Patrick asks for a "volume-teer" from the audience.
Patrick pronounces "Open Sesame" as "open recipe!"
Benjamin Franklin's proverb "Early to bed and early to rise makes a man healthy, wealthy, and wise":