Character mistake: Another identity mistake in the finale: When Beast Boy's team is initially subdued, we see honorary Titan Hot Spot standing amongst the villains even though he is a) a hero and b) is supposed to be frozen solid at that time.
The Calculus Affair: Part 2 - S1-E13
Character mistake: After reaching the border, Snowy finds an umbrella and Tintin states that it is Calculus's umbrella. It isn't Calculus's umbrella - Calculus's umbrella has a brown handle, and this one has a grey handle. (00:42:25)
Character mistake: The first time Arnold tries Rhonda's marriage predictor test, he says his favorite number is five, but Rhonda actually makes six moves. The second time, Arnold says it's three, but Rhonda counts off four.
Character mistake: In the third instance where Superman manages to get rid of Mxyzptlk, he uses an article full of typos which spell the latter's name backwards as KLTPZYXM. Among the incorrect words is the word "citrimes", in which Superman has included an I and a T, so the correct word in context with the rest of the text should read "crimes" and thus the errors would spell KL-I-TPZYXM. Since there are no vowels in MXYZPTLK, however, what is the additional I doing here - and why didn't Mxyzptlk bother to mark it as a mistake, either?
Behold, a Distant Star - S2-E10
Character mistake: When Sue is brought out of surgery, her father can be seen wearing a watch. Surgeons don't wear watches or any other kind of jewelry when performing surgery, as they can't be sterilized and can also get in the way of gloves. (00:05:00)
The M.O.D.O.K. That Time Forgot! - S1-E2
Character mistake: M.O.D.O.K. refers to Hoobastank as "the Beatles of the late 90's." Hoobastank only released one album in the 90's, and they didn't become popular until after they released their second album in 2001.
Character mistake: Despite being a Greek mythology buff Maxie Zeus says "Vulcan" when he meant "Hephaestus" the Greek god of fire and the forge when he first spoke with Batman.
Mystery on the Prarie - S3-E14
Character mistake: If Chris and Martin are creature experts, they would have already known the buffalo birds are nest parasites.
Life's Ruff - S1-E20
Character mistake: When first showing the Florida State Poochitentiary, the white sign in front of it misspells the name as "Florida State Poochitentary." (00:06:41)
Character mistake: Shaun says that the underground facility is "built like a bunker", but the single missile they dodged just created a huge hole a moment earlier. (00:11:40)
Mine Your Own Business - S1-E4
Character mistake: When Shaggy and Scooby order Sarsaparilla at the saloon, Scooby says "Two" but he appears to be holding up three fingers.
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.
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)
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)
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.
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.
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)
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.
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: The title card says "Plummers Academy" instead of "Plumbers Academy."