|"Ben 10/Generator Rex: Heroes United"|
|Season 3, Episode 10-11|
|Air date||November 25, 2011|
|Written by||Man of Action|
|Directed by|| Chris Graham|
"Assault on Abysus"
|Images | Quotes | Transcript|
"Ben 10/Generator Rex: Heroes United" is an extended crossover episode of Generator Rex with a guest appearance of Ben Tennyson from Ben 10: Ultimate Alien. It debuted on November 25, 2011. It is also a two-part episode and the 10th and 11th episodes of season three of Generator Rex.
Rex teams up with an alternate superhero, Ben Tennyson, to save the Earth from a deadly Alpha Nanite that entered New York through a swirling vortex, the same way Ben arrived in the city.
Hovering over the city of New York, a mysterious dimensional rift begins to form and imposes sporadic shocks capable enough to destroy corporate buildings. Providence flies over to investigate to get an up close look and on Black Knight's mark, the Keep shoots directly at the distortion as an attempt to close it. Via her screen, Black Knight asks Caesar about what exactly that dimensional rift is, but even Caesar replies that he has no clue. Before she could hear more, White Knight takes over her screen and demands that she lets their agents assist them. Meanwhile, Six and Rex train in combat while Rex complains that all heroes except him have a theme song (he brings it up by saying that he doesn't need anything more - except a theme song). Rex sings it (it is based on the original ben ten theme song) while defending himself. Then, promptly after Rex finishes his song, Six beats him. He admits that it's catchy, but warns that everything he cares about can vanish. Interrupting their session, Dr. Holiday informs them about the situation in New York.
Quickly, Rex, Bobo and Six arrive at the scene and Rex flies at a close proximity to the rift, trying to destroy it. Suddenly, Ben as Humungousaur falls from it and, mistaking Rex for an alien, punches him into the pond. After another creature is churned out of the rift, Rex tells Six that he will take care of Ben (Rex thinks Ben is an EVO) while Six should go after the other unsolicited guest. Transforming into Diamondhead, the two have a sword fight across the pond, and then, with Ben as Lodestar, take up their fight all the way towards the city. They accidentally knock a giant sign over the building that nearly kills the New York citizens until Rath rescues them, leading to Rex realizing he is not exactly the bad guy. No one seems to be aware of who Ben is, so he transforms back to his human form with hopes of “clearing their memory.” Unfortunately, it doesn't work.
Rex spots Six in the middle of fighting the other creature, who is about to blow up. Sacrificing himself to cripple the enemy, Six goes unconscious. Rex returns with Six in a coma to base. White Knight reveals that the enemy emitted some sort of energy containing itself before exploding and orders Rex to search for it. Ben, being retained in a tube, offers to help, but Rex is angry at Ben, and blames him for Six's condition. Promptly, Ben escapes the base as Big Chill while Rex is chasing after him, along with a trail of red mist.
Both end up in where Bellwood should be, revealing that Mr. Smoothy is replaced with Bob’s Biscuit Barn and confirming Ben’s speculation of being in another dimension. After hearing how the realization affects Ben, Rex and he come to a truce. Then, they come across Caesar, who seemingly poses a weapon aimed at them until Diamondhead deflects its energy and destroys the device. However, Caesar claims that he meant to aim it at the creature behind them in its ghostly form, who he reveals to be the Alpha Nanite.
Alpha asked for Caesar's help to obtain a stable and lasting physical form, but Caesar refuses and escapes to his mobile lab. He further clarifies to Rex and Ben that he created Alpha to control other nanites as a sentient being, but began to use its powers to use other living beings as hosts. Therefore, he was forced to send Alpha to a parallel universe, the Null Void, assuming it was an empty space. However, Ben interdicts that Alpha must have absorbed alien life to develop its current form. Before they could continue their conversation, Alpha attacks and destroys the lab, leading to Caesar escaping in an escape pod while leaving Ben to protect Rex using Cannonbolt.
The two proceed to the petting zoo at the Providence Defect Base when Alpha arrives to attempt to absorb the EVOs' nanites as well as Rex's Omega nanite. Once Dr. Holiday, Rex, and Ben drive him off, Rex and Ben play a basketball game, revealing their backgrounds. Interrupting their game, White Knight calls the two to inform them that Alpha is in the Bug Jar. As they both go, they pick up the wrong jackets, causing Rex to mention how his feels tight and Ben to ask why his smells like bananas. Bobo retorts that if they are their only hope, the world is doomed.
When White Knight, Ben, and Rex arrive at the Bug Jar, Alpha has already absorbed the entire nanite population and develops a stronger form. Grabbing for Rex, Alpha stops Ben, as Diamondhead, from interfering by hacking the Ultimatrix to transform him back into a human.
He proceeds to drain Rex of his nanites until the Omega prevents him from doing so further. However, Alpha absorbs some of the Ultimatrix's power, transforming into corrupt forms of Heatblast, Four Arms, and Humungosaur. Rex attempts to hold him off while Ben continues to try to resurrect his watch. Eventually succeeding, he turns into Shocksquatch and manages to stun Alpha temporarily but quickly reverts to his old self.
White Knight holds off Alpha for a while until Rex disables his Ultimatrix powers. Unfortunately, Alpha whisks away Rex's Omega nanite and evolves into an even stronger form, absorbing ruin structures to increases its nanites. Although Rex loses some hope with his Omega builds gone, Ben manages to come up with a scheme. Transforming into Upgrade, Ben merges with Rex to enhance his builds and the two heroes rush to combat Alpha. Despite managing to cut it down, Alpha restores his limbs and is unaffected by their attempts. As a last minute plan, Rex summons his Slam Cannon, using Ben's Cannonbolt as his ammunition, and aims directly at the Omega Nanite with his enhanced goggles. They succeed in diminishing Alpha's form into a mere dense ball while Caesar arrives, capturing Rex's Omega nanite just in time. Caesar opens another rift to Ben’s world, prompting Ben to contain Alpha as Upchuck and departs back to his world, though weirding out Rex at the same time.
Returning to the base, Rex attempts to visit Six, although Bobo and Dr. Holiday to notify him that he is fine. Relieved, Rex attempts to conceal his happiness when Six arrives, but then proceeds to hug him. Rex expresses hope in seeing Ben again, but Dr. Holiday is quick to point out that, with infinite timelines in the multiverse, running into the version of Ben who knows him is next o impossible. Six, however, believes some meetings are destined to occur and assures Rex that he may yet see Ben again, until Caesar surprisingly appears, bypassing their security system. Caesar then re-injects the Omega into Rex's bloodstream, assuring him it is not the Alpha. Meanwhile, swirling in the Null Void, Alpha somehow glows and manages to crack its compact shell.
(* Indicates debut)
|Daryl Sabara||Rex Salazar|
|Yuri Lowenthal||Ben Tennyson*|
|Wally Kurth||Agent Six|
|John DiMaggio||Bobo Haha|
|J. K. Simmons||White Knight|
|Jennifer Hale||Black Knight|
|Freddy Rodriguez||Caesar Salazar|
|Dee Bradley Baker||Humungousaur*|
- As Rex holds unconscious Six in his arms, the man doesn't have his shades on but at the next scene they are present on his face.
- While still in a coma Six is wearing the same shirt Ben wears.
- When Ben is talking about his aliens, in the picture of the aliens, one of Ripjaws' eyes is violet, while the other is green.
- When Ben turned into Upgrade, the Ultimatrix symbol isn't on his chest.
- This crossover is "a part of Generator Rex's regular production cycle".
- At the beginning of the episode, as the Keep entered the scene, a neon light of the E.V.O. Guys was present on a billboard on one of the buildings.
- Rex's and Ben's cities are both named Bellwood, but they're different towns. 
- While training with Six, Rex tried to come up with a theme song for himself. The tune he came up with resembles the original Ben 10 theme song.
- Rex also shortened "Generator Rex" in the name of the show to "Gen Rex".
- Ben and his alien counterparts are animated in the Generator Rex art and animation style.
- The episode is approximately 43 minutes 54 seconds long.
- Ben's team, his cousin Gwen Tennyson and Kevin Levin, do not appear in this special, though they are mentioned by Ben to Rex as people he cares about along with Grandpa Max. They are shown in a group shot of the four plumbers as Ben explains his Earth.
- Ben transformed into a new alien, Shocksquatch, who was first shown as a TKO robot.
- A flashback of Ben as a 10-year-old kid was seen and mentioned.
- A lake where Rex was thrown by Humungousaur resembles the symbol of the Ultimatrix.
- When Ben said his name to Rex, the Ben 10: Ultimate Alien theme song was heard.
- In his own series, Ben almost always cries out the name of the alien he has just turned into, and also uses the Ultimatrix's ability to evolve aliens to their "ultimate" forms, which are stronger and more combat-oriented than their original forms. He does neither in this crossover.
- This episode made it to the Top 100 on iTunes.
- After Rex crushed Ben while he was Rath He had said this Let me tell you something robotboy! This may be a possible reference to an old cartoon network T.V. show Robotboy
- ↑ 1.0 1.1 Harris, Jeffrey (2011-07-25). "SDCC2011: Generator Rex/Ben 10 Crossover Special Set For Thanksgiving". Toonzone. Retrieved 2011-07-25.
- ↑ Information taken from  based on live chat with Man of Action