The first feature film of the Ben 10 animated series. For the overall series it's actually the second film in the franchise coming after Ben 10: Race Against Time as well as the second based off the original series. It's also the Grand Finale canonically and in official order of the series (designated as episodes 49-51) despite that it was produced and took place before the last 10 episodes of the series and aired between Big Fat Alien Wedding and Ben 4 Good Buddy in Cartoon Network airing order.
An encounter with Dr. Animo accidentally sets off a self-destruct protocol in the Omnitrix. Tetrax reappears, and tells Ben that, in order to stop the countdown (the ramifications of which Tetrax doesn't reveal until later), they must find the only being who knows the inner workings of the device: its creator, Azmuth. Tetrax takes Ben (and Gwen, who stowed away on the ship) on an inter-stellar journey that's anything but leisurely, and that's before considering that Vilgax is hot on their tracks...
This movie provides examples of:
- Actually, That's My Assistant: Tetrax picks up a DNA signature on the watch, thinking it to be Azmuth's, and traces it to Incarcecon. The signature actually belonged to Azmuth's ex-assistant, Myaxx. The trip to Incarcecon wasn't a total loss, however, as Myaxx was able to lead the group to Azmuth's hideout.
- Asteroid Thicket: Azmuth's planet is surrounded by a dense asteroid field, made worse because he has set up a light-dampening field which prevents anyone from seeing the asteroids.
- Attack of the 50-Foot Whatever: This film introduces Way Big, a giant alien form.
- The Alcatraz: This is first appearance of the prison station Incarcecon.
- Apocalypse How: The Omnitrix's self-destruct protocol can cause an X-4.
- Blackout Basement: Azmuth's world has a device which absorbs ambient light, making it nearly impossible to see the asteroids surrounding the planet.
- Disney Death: Gluto is blown up by a blaster during a Heroic Sacrifice and Gwen is seemingly eaten by a feral Wildvine, but both turn up alive during the final battle, the former having regenerated from bits left on Gwen's clothing then rescued her.
- Dude, Where's My Respect?: Myaxx left Azmuth's employ because he never gave her credit for the work she did for him. He's pretty upfront that he probably won't get any better when he gives her her old job back, but she figures it's better than prison.
- 11th-Hour Superpower: At the movie's climax, Azmuth gives the freshly-repaired Omnitrix back to Ben, with a new alien: Way Big.
- Grand Finale: To the original series canonically and official order (before the non-canon Goodbye and Good Riddance).
- Interspecies Romance: There's some Ship Tease sprinkled between Gwen and Gluto; primarily on Gluto's side, but Gwen isn't unresponsive. Invoked and lampshaded (and curiously played up on her side) by Ben:"Great! Gwen's in love with the snot blob."
- I've Come Too Far: Said by Ben in a moment of Heroic BSoD after Gwen supposedly dies when they're right outside Azmuth's door.
- Madness Mantra: "It should've been me, It should've been me," says Ben after he thinks Gwen has been killed.
- Running Gag: Tetrax, regarding his friend Gluto having never-before-mentioned abilities."Who knew?"
- Taking the Bullet: Gluto wraps around a blaster aimed at Gwen, and is splattered by the discharge. He gets better.
- The Man Behind the Curtain: Ben Tetrax and Myaxx finally reach Azmuth who appears to be a giant creepy figure with an ominous voice. However, it is revealed to be a biosuit which Ben destroys and Azmuth is actually a tiny frog-like alien from the same species as Grey Matter.
- To Serve Man: Tetrax offers Ben and Gwen a disguise for Incarcecon, as some aliens consider humans a delicacy.
- Wham Line: "Not just you, of course," spoken by Myaxx about the self-destruct and escalates the core threat of the movie to universal proportions.
- What the Hell, Hero?:
- Myaxx asks Tetrax if he's actually told Ben what would actually happen if the Omnitrix's self-destruct protocol wasn't shut down. When Ben learns the truth, he gets angry at Tetrax for hiding it from him.
- Gwen likewise gives one to Ben as they get further to the hideout for his supposed lack of empathy after they seemingly lose Gluto and on if he likes being the hero sorely for the glory of it rather than genuinely trying to help people.
- Myaxx gives Ben one when he activates the Omnitrix which he knows will speed up the self-destruct countdown.Myaxx: What have you done?!
Ben: I ask myself that question all the time.