Character mistake: The title card says "Plummers Academy" instead of "Plumbers Academy."
Timmy the Barbarian/No Substitute for Crazy - S5-E18
Character mistake: In 'No Substitute for Crazy", When Timmy and Sanjay are leaving the school after Mr. Crocker falls down the well, a few cats come up to them and he introduced an orange one as "Omar." Later, when Mrs. Sunshine is leaving after being substitute for a day, Sanjay has cats around him and comforts "Omar", except he says this to a red cat, not an orange cat.
Character mistake: When Cheryl, Pam and Alan Shapiro are talking on the movie set, the store behind them has a typo: Stationary should be spelled "stationEry'. (00:10:30)
Champion vs. Creator, Part II - S1-E27
Character mistake: Pegasus says his toon world cannot be penetrated, but that is not true since it's a magic card, so any card that destroys magic cards can destroy it. Furthermore, monster special effects can also destroy it.
Yomigaere! Eiyuu Densetsu - S1-E1
Character mistake: Not to dispute physics in an anime about people drawing arcane cosmic powers from constellations, but when Marin explains to Seiya what happens when you shatter a rock into smaller pebbles, she says that you "destroy its atoms." That's not how physics works and luckily for her, Seiya and everyone else in Greece at the time, she did not create a nuclear fission in the palm of her hand just to prove her point.
Until Sunset, the Full Moon - S1-E7
Character mistake: Zenigata uncovers Elena's arm saying he noticed the mark when she was fighting "those guys previously." Which guys? Her assailant was just one dude. (00:13:40)
Wax Doll Castle Murder Case: File 2 - S1-E8
Character mistake: Hajime's proposed solution is obviously wrong, but not for the reason they mention; the 'killer' could never clean themselves up completely and effortlessly in such a short time from the soot.
Invasion of the Ferb Snatcher/Ain't No Kiddie Ride - S2-E28
Character mistake: In 'Ain't No Kiddie Ride' Carl reminds Major Monogram that he has no sense of smell and that he was born without nostrils noting it on his resume. But in 'Brain Dead' when Major Monogram sees Perry wearing a face mask he points out that Carl is also a germaphobe. Carl corrects him saying "It's not the germs sir, it's the garlic smell." He wouldn't be able to smell anything since he has no nostrils. (01:10:00 - 01:35:00)
Character mistake: Bessie's last name is misspelled "Higginbottom" on the newspaper Happy shows her.
Six Forgotten Warriors Chapter 4: The Six Fight Again - S5-E5
Character mistake: When the Red Skull reemerges from the vortex, he sees Chameleon and acknowledges him as his stepson. However, only moments before this, Kragov explicitly stated that the Chameleon was more like an adopted son to the Red Skull.
Character mistake: After Anakin says to use the walkers (AT-TEs) as boarding vessels, Rex calls the first one an AT-AT (a vehicle that does not even exist at this point in-universe) while ordering a battalion of clones into it. (00:04:10)
Coming Home - S1-E13
Character mistake: Kamaria Ray thinks back of her son shooting at the Zeon troopers with a mental image that is wrong; Amuro was not shooting from the bed, but from the door. (00:15:20 - 00:19:20)
The Hairy Scare of the Devil Bear - S1-E8
Character mistake: Velma says bears only have four claws. Wrong, they really do have five claws.
Character mistake: The episode opens showing "The LLUSTRATED morning " newspaper. Yes, it is missing the letter "i." (00:00:15)
A Frightened Hound Meets Demons Underground - S1-E14
Character mistake: Velma mentions Seattle burned down in 1890. The fire went from June 6-June 7 1889.
Character mistake: Lucy Liu-bot says Fry's name normally, but uses an automaton voice for "Can eat more", when she has always used Fry's name as a Text-to-speech type of automaton voice. (00:07:45)
Burple Nurples/Shnitzel Makes a Deposit - S1-E2
Character mistake: In "Burple Nurples", Chowder was selling Burple Nurples for 5 dollops each. Later, Mung Daal steals a tray of six Burple Nurples, and Chowder runs after him, telling him that he owes him 300 dollops, instead of 30.
Suggested correction: The tray had more than 6, even if it was drawn to look like just 6, they could have been stacked on top of each other. Later when they're dumped in the fire, you can see more than 6 go in. Plus at that point we don't know how much Chowder was selling them for since it was after Mung Daal (while in disguise) paid more than 5 dollops for one.
Character mistake: Dexter's father says he'll stunt jump over four school buses, but only three are shown.
Character mistake: Jaden tells Damon that because of Elemental Hero Flame Wingman's ability, he will lose life points equal to half his destroyed monster's attack points. This is incorrect, as Damon will actually lose life points equal to the full attack points of the destroyed monster. He has used this card multiple times throughout the series, so this isn't a mistake he should have made. (00:18:25)
Takishîdo wa kaze ni mau - S1-E1
Character mistake: During Lucky's initial display of power at the gates of the settlement, he fires a cannon shot at the building and shouts (in the English dub) "How do you like that? Bullseye." There's a view of the building and you can read the horseshoe sign; "Evergreen SHOPING Mall." (00:07:15)