Take Me out of the Ball Game - S3-E24
Other mistake: When Peggy strikes Bill in the head in the softball game, he gets hit on the left side of his head. Later in the scene he is using an ice bag on his head but he's icing the other side.
Other mistake: In the scene where Drakken accidentally "clones" Bonnie Rockwaller instead of Kim Possible, he holds up a picture of Kim to compare the results of his experiment with the real thing. The Bonnie clone, completely encapsulated behind the glass of Drakken's cloning machine (as evidenced by the reflection of light off of it) somehow manages to get a hold of the picture despite this barrier. (She does this without having to break the glass.).
Other mistake: Tails automatically knows Cosmo's name even before she introduces herself later on (English Dub version only).
Don't Fool With a Phantom - S2-E8
Other mistake: When the wax phantom appears behind Scooby and Shaggy the man who supposedly is impersonating him in the suit is in clear sight directly behind Fred Daphne and Velma.
Hot-Rodding Teenagers from Dimension X - S1-E4
Other mistake: General Traag's weather weapon causes a blizzard across the city, yet when the Turtles and the Neutrinos come up to the surface after the blizzard had been occurring for a while, none of the cars parked on the street, including the Neutrinos' two flying convertibles, are covered in snow. The interior of their cars should have been full of snow.
Heart of Ice - S1-E3
Other mistake: When Batman is watching the security footage of Victor Fries' accident, at first Fries is addressing the camera directly which follows him and pans according to his movements and Ferris Boyle interrupting him, which would suggest a second person was in the room with a handheld camera. But after Ferris Boyle enters the room and orders Fries' experiment terminated, there are several cuts from various angles in the room suggesting surveillance cameras. The surveillance style footage also often conveniently cuts to the face of whichever person happens to be speaking or will cut to a certain angle in order to put emphasis on the action, all of which would require multiple mounted cameras and purposeful editing by either Boyle or one of his subordinates, which would be completely illogical since they don't want anyone to see the footage in the first place. (00:12:20 - 00:13:55)
Other mistake: When LB comes into Tweeg's room and he sees him covered in spots and he is discoloured he freaks out. Why does he freak out? He just saw Tweeg in the previous episode all covered in spots so he should know that it's him.
Other mistake: It appears as if Steve is holding 3 $20 bills when he supposedly received $50.
The Great Egg Heist/The Feud - S2-E9
Other mistake: In the Great Egg Heist, when they arrive at the museum, Jimmy gives everyone shishkabob-shaped earplugs for Libby's scream. But in the next shot, if you look at everyone's ears, there are no earplugs. Also, in the next shot, next to Libby you can see Carl putting his hands over his ears. This is impossible because the pointy ends of the earplugs would stab Carl's hands.
Other mistake: In the voice cast list, the Groom's Father appears twice - with two different voice actors - and the Groom's Mother is not even listed.
The New Kid - S1-E2
Other mistake: At the start when the gang change the time on the clock in the classroom, it wouldn't control the main school clock, plus in every other episode the clock has been operated by The Box on the side of the school, as shown in " The spy who came into the playground".
Other mistake: The Time Expansion Helmet was supposed to allow Dexter to perform his 30 minute morning task in 30 seconds. Since this is the case shouldn't the cat have hit the fishbowl ages ago as time is not frozen.
The Elements of Harmony (2) - S1-E2
Other mistake: At the end of the episode when Princess Celestia is talking to Twilight Sparkle you can see that Princess Celestia's tail is on top of her leg instead of in-between. It's covering her cutie mark.
The End of Flutter Valley (2) - S1-E2
Other mistake: As the Stonebacks begin to destroy the bridge the Ponies call out for help. As the bridge moves up and down, locks of Gusty and Baby Cuddles' hair flash white. Baby Cuddles is also drawn in a deformed fashion with no neck and two rumps.
Other mistake: In the closed-captioning, when Arnold and Gerald "touch thumbs" (and you hear that "sproing" sound), the caption says "[glass shatters]"
The Thrice Cream Man/The Flibber-Flabber Diet - S1-E7
Other mistake: In "The Flibber-Flabber Diet," Chowder and Truffles return when Mung calls them. How could they hear him when they'd already left?
Other mistake: Beast Boy and Wildebeest fight in a cage suspended in an endless room, with no solid ground underneath. But during the fight both combatants keep stepping onto the gaps formed by the cage bars without their feet falling through, as if the cage bars on the bottom side are merely painted onto a solid surface. For instance, watch Beast Boy's feet when he turns into a skunk.
Other mistake: After helping Longshot in the alley, Jubilee tells Logan "Are you blind? He's on our side!" to which Logan responds "We don't know that." This dialogue is repeated verbatim when the Professor meets Longshot. In addition to being obviously re-used vocal lines, the context of Jubilee asking "Are you blind?" doesn't make much sense the second time.
The Origin of the Fantastic Four: Part 1 - S1-E1
Other mistake: When Puppet Master is making a clay figurine of Thing, the mold he uses doesn't have a Thing-shaped interior with which to make a detailed figurine. The figurine should have just looked like an undefined human-shaped figure. (00:15:20)
Other mistake: In the scene where Yakko, Wakko and Dot are sitting at their desks repeating Miss Flamiel's every word, Wakko is drawn without legs (only feet) during one shot.