Ben 10 (2005) - 33 mistakes in entire show

Continuity: Season 4, episode 9 "Ben 10 vs. The Negative 10, Part 1": When Charmcaster waves her good-bye to Gwen just before Animo swoops her up, the coloration of her waving sleeve's decor suddenly changes from violet to purple.

Plot hole: When the Corrodium Beam is shut down, there is a brief scene of the sky clearing at Mount Rushmore. But on the cliff face all four heads are seen, whereas the head of Theodore Roosevelt got crumbled in "Secrets," and it's too far forward to have been carved into the mountain face, in place (and same position) of the old head, yet again.

Revealing: Season 4, episode 5 "Ben 4 Good Buddy": When the Baron drives off from the garage in the Rust Bucket, the VR's interior shifts unnaturally; an obvious glitch in the computer animation.

Revealing: It is strange that the news coverage at the beginning of this episode is able to cover the story from all angles in such rapid succession: from the helicopter straight to the ground, then even a close-up of the goon atop the crystal mount Diamondhead traps him on.

Continuity: When the Krakken snatches the Cannery crate from the boat, you can see that the lower horizontal bar from the 'E' is suddenly missing, thus reading 'Cannfry'.

Continuity: When Ben pretends to be sucked into the lake, and Gwen turns around to look after him saying "I'm not falling for it", she's missing her eyebrows for a second or two.

Continuity: When Rojo attacks the police academy, there is a patrol car right behind her. But when Ben (as XLR8) arrives and slams into her, the car suddenly vanishes.

Plot hole: The alien mummy is found by the werewolf in a separate rectangular block of concrete. However, I don't think that the Tennysons would have made the effort of first enclosing the mummy in a separate load of concrete, waiting until the stuff is hard, then putting it into the hole and covering it with a new load of concrete. Too much effort and too little time for one night ("Under Wraps"), since concrete does take time to get hard properly.

Other: 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.

Plot hole: When the mutated sea gull attacks the Tennyson's' sailing boat, it brings down the sail. But then the piece from under which Ben and Gwen emerge suddenly has a convenient wooden lattice fixed to it, whereas in reality it should have none.

Continuity: Season 4, episode 10 "Ben 10 vs. The Negative 10, Part 2": When the Forever King makes his announcement "Nothing will stop this little home-coming", he stands outside the Mount Rushmore base on bare soil. But in the scene where Max reviews the recording of this speech, all of a sudden we find the Forever King standing on a neatly tiled floor.

Continuity: Fourarms Gwen launches four bowling balls with all her arms at the same time, but the balls strike the pin sets one at a time.

Plot hole: 4-9 "Ben 10 vs. the Negative 10 (Part 1)": Rojo (from first season's "The Alliance") makes her second appearance in the series in a suit of powered armor. However, in "The Alliance" she had been turned into a cyborg by Vilgax' drone and thus looked radically different than she does here. So how can Max say: "How did she get back her alien tech?" when her equipment and weaponry was totally different in their first encounter?

Deliberate "mistake": When the Tennysons drive towards the city's power plant, Grandpa Max is using the left side of the highway instead of the right. Even with a looming nuclear accident, correct traffic habits do play a role, especially on such a narrow highway. Who knows whether one might drive down the road in a hurry and you approach him on his side of the highway?

Plot hole: In Ben's nightmare, Gwen says, "We will come and get you!" and then she nags at Ben for being the one with the alien powers, and she does not join him in climbing the tree. My guess is that this was due to a script error; it was likely supposed to be "he" (i.e. Ben) instead of "we".

Factual error: It would be highly improbable for Kevin to find Vilgax frozen deep in space. As we see in first season's episode 'Secrets', Vilgax's ship was blasted apart in the upper atmosphere - after all, Ben escaped as Heatblast, and he wouldn't have been able to once beyond the stratosphere. Earth's gravitational pull would have kept Vilgax on Earth, not released him into deep space.

Continuity: The number of rockets Sixsix has on his wrist launcher alternates between three and four, especially during the final combat scenes.

Plot hole: After Upgrade has successfully removed Rojo's cybernetic parts, the beam rifle she had used in the armoured car heist at the episode's start suddenly appears among them. But when the drone merged with her, she wasn't holding the gun and so it couldn't have been transformed along with her.

Continuity: Season 4, episode 10 "Ben 10 vs. The Negative 10, Part 2": As we could see in first season's final episode, "Secrets", Roosevelt's head on Mt. Rushmore was totally destroyed, and in most subsequent episodes - including this one's first part - there is a sizable hole in its place. But after Ben asks whether the plumbers' hologram technology can replicate 'big presidents', and the scene changes to the demolished presidents' heads, the crown of Roosevelt's head suddenly joins the others on the mountainside.

Continuity: When Ben, Gwen and Max try to track down Ghostfreak, Max's scanner picks up "trace spectral activity from around that corner", which happens to be right ahead, but then Ghostfreak and cohorts appear from behind. In a deleted scene featured on the series' DVD, the source of the reading is revealed to be the tuba player Ghostfreak had possessed, who instantly runs off at the sight of Fourarms.