34497a3fe0ef52949a1ba8e99894ed69 This article belongs to the Classic Continuity

Undercover is the eighteenth episode of Ben 10: Alien Force.


The episode begins with Ben's Team trying to repair Professor Paradox's teleporter that was broken by Kevin. Ben and Gwen are slightly nervous and Kevin activates the teleporter, but it doesn't work and starts to explode. Ben transforms into Swampfire in order to deactivate it, but the control panel dies. Swampfire lifts it and throws it. It breaks and explodes. The team is safe and Swampfire transforms back into Ben. Kevin freaks out because the teleporter is destroyed and says he knows someone who can fix it: a kid named Cooper. Ben and Gwen realize that it's the same Cooper that helped them fight the Negative 10 and the team drive to Cooper's house, but he isn't home. Kevin says that he never leaves his lab, so he breaks in and the team goes into the lab. They discover that it is messy and Ben accidentally opens a message Cooper left showing him getting captured by DNAliens. Fortunately, Gwen tracks Cooper to Los Soledad, but it is shown to be empty. Ben enters into it and disappears. Gwen and Kevin follow him inside and the team discovers that it was cloaked from the outside - inside is a snowing DNAlien city.

The team hides and formulates a plan. Ben perceives that the DNAliens are building a giant arch and the team goes to the building where Cooper is in while having to hide from DNAliens. They enter the building Cooper is in and make their way to him. Ben transforms into Goop and enters into Cooper's room, where he sees Cooper with two DNAliens. He watches Cooper accidentally make a sound with two pieces of metal that floors the DNAliens. The DNAliens surround him, but Goop attacks and defeats them. Kevin and Gwen break in and see the two defeated DNAliens. Goop transforms back into Ben and the four leave and try to exit the base. Cooper fawns over Gwen and Ben says that they've walked in on the biggest DNAlien plan they've seen. Cooper says that he can shut down the cloaking projector and pulls out a prototype cloaking device that can cover the four. They are now invisible and run to the cloaking device. However, their cloaking device malfunctions and they are seen by the DNAliens, who swarm at them.

The DNAliens manage to grab Kevin, Cooper, and Ben. Gwen tries to fight them, but she is defeated. A Highbreed arrives and tells Cooper that he's going back to work, or else the team will pay the price. After Cooper agrees, the DNAliens bring the team to Cooper's lab and locks them in. Ben remembers how the metal sound dropped the DNAliens. Kevin absorbs the metal and Ben transforms into Echo Echo. Gwen tricks the guards into opening the door and they escape from the cell. Gwen hits the metal and Echo Echo amplifies the sound, knocking out the DNAliens. More DNAliens chase them, but they fight them with the sound. They go to Cooper, who is working on a machine for the DNAliens. The DNAliens that were guarding him drop at the sound. The four run from the DNAliens and Gwen and Kevin try to fight them, but they become surrounded by DNAliens. Cooper says that the cloaking device is near the arch. A DNAlien grabs Cooper, but he manages to break free and Kevin punches the DNAlien away. They create one more sonic blast, knocking out all of the DNAliens.

The team arrive at the arch and Echo Echo transforms back into Ben. Cooper touches the device, but has a vision of the arch activating and Highbreed ships coming through and destroying Earth. He tells the team, but Ben tells him to destroy the cloak. He telepathically lifts and destroys it. A truck drives to Los Soledad and it uncloaks, confusing the driver. Gwen destroys the cloaking device's parts, but DNAliens arrive and shoot at the team. They manage to run and enter into Kevin's car before driving away. The Highbreed tells the DNAliens not to pursue. Ben says that they need to go back and find out what's going on. Cooper agrees to help. Later, at Los Soledad, the police arrive and investigate due to being tipped off by the driver. The Humans that were present tell the sheriff that they are building a mall and he drives away. When they go, the people remove their masks to reveal a Highbreed and DNAliens.

Noteworthy Events

Major Events

Character Debuts

Minor Events

  • It is revealed that DNAliens cannot handle very high-frequency sounds.



Aliens Used



(after the teleporter pad was destroyed)
Ben: Is everyone alright?
Kevin: Forget that, what about the Teleporter Pad!
Gwen: Deep down, he's really glad we're okay.
Ben: At least we don't have to worry about any "banana-fly" monsters.

Quotes Right


Kevin: So, Gwen... happy to see your ex?
Gwen: Zip it! (to Ben) You just had to mention the crush?
Ben: Probably not.

Quotes Right


Cooper: (to Gwen) The way you came storming in there, like how Princess Elena rescued me last week from the Caverns of Unforgiving Dismay!
Gwen: Excuse me?
Cooper: In Nations of Conquest, the M.M.O.R.P.G I play.
Gwen: Excuse me?
Cooper: Massive multiplayer online role-playing game.
Kevin: Yeah Gwen, and your power is being plus-3 nerd bait.

Quotes Right


Gwen: Ben? Are you hiding?
Ben: No. It’s just, if a fly lands on that banana when it teleports and it rematerializes as a deathly banana fly monster. I don't wanna be standing right next to it, is all.

Quotes Right

Naming and Translations

Language Name Origin
French La Couverture The Cover
Hungarian Aligátorbőrben Aligatorskin
Portuguese (Br) Camuflagem Camouflage
Spanish (HA) Un Viejo Conocido An Old Acquaintance
Spanish (Spain) Encubiertos Undercover


Voice Actor Role(s)
Yuri Lowenthal Ben Tennyson
Ashley Johnson Gwen Tennyson
Greg Cipes Kevin Levin
Dee Bradley Baker Swampfire
Echo Echo
DNAlien #1
Richard McGonagle Highbreed
Guard #2
Kevin Michael Richardson DNAlien #2
Guard #1
Corey Padnos Cooper Daniels


  • When Kevin said to Ben "You used to turn into one of those (insects)", he was referring to Stinkfly.
  • Ben's concerns about a "banana fly monster" in the beginning of the episode is a reference to the science-fiction horror film The Fly, the main character had a similar problem when he and a fly entered the teleporter he was working on at the same time transforming him into a fly monster.
  • The teleporter is very similar to Paradox's time machine.
  • The second hint towards the events of War of the Worlds are foreshadowed when Cooper was destroying the machine.


  • Though Kevin shows tendencies of being protective, jealous and mad when other guys had a crush on Gwen, he was surprisingly good humored towards Cooper for his adolescent feelings for Gwen.
  • Echo Echo's voice in this episode is deeper than usual.
  • On DVD's print of this episode, The ending credits was fading in and out.
Ben 10: Alien Force Episodes

Start a Discussion Discussions about Undercover

  • How did Highbreed got back to earth?

    2 messages
    • Last time i checked on season 2 eps 2, Ben left Highbreed in desert planet. But in this episode, suddenly Highbreed is on earth with the DNAli...
    • Different Highbreed. The Highbreed are a species not a person.
  • Why wasn't Kevin troubled by Cooper's crush on Gwen?

    2 messages
    • Other times people have crushed on Gwen Kevin has been jealous and protective, so why didn't he react like that around Cooper? In fact...
    • He knew Cooper didn't stand a chance. Gwen had interest in Morningstar because he was a stunning womanizer that acted sensit...
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