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Birds of a Feather is the twenty-third episode of Ben 10: Alien Force.


Ben, Gwen and Kevin are surrounded by a large amount of DNAliens near a forest. Ben transforms into Spidermonkey to fend them off. As Kevin and Gwen have a hard time handling them, a different Spidermonkey, who's assumed to be Ben by Kevin, helps. To their surprise, it fights insanely until Kevin says, "Man, I have never seen you fight like that." Spidermonkey didn't answer, making them realize that it wasn't Ben. Afterwards, his name is revealed to be Simian, and Ben thanks him and wonders what he can do to make it up but Simian wanders back to the forest. While Ben is home wondering about who Simian was, Gwen and Kevin toy around with an acid dispenser dropped by the DNAliens from their battle earlier.

Goop finds Simian again, this time at a cryogenics laboratory stealing a piece of scientific equipment. After Goop scolds Simian for being a thief, Ben takes him to a place where they build a bonfire. There, Simian reveals himself to be the prince of Arachnichimps and that his dad, the king, died when he Simian was finishing school. He cuts to the chase and reveals that the only way he can prove his worth as a king is to retrieve a missing crystal which is the symbol of monarchy on his planet. Ben offers his help but Gwen and Kevin are skeptical. But they are swayed by Ben's argument and decide to go to the fortress on the moon where the crystal is held.

As the gang infiltrates the fortress, Ben and Simian venture into the deepest unknown corridors when a sinking-ceiling trap separates them from Kevin. Ben trips a silent alarm and awakens a single guard named Lu in his command center. Appearing quite frightened and not expecting intruders, Lu politely orders Ben and Simian out of the fortress, only for Simian to destroy the speaker. When they come to an impenetrable door, Ben transforms into Big Chill and freezes it to a brittle so Simian can break it down. Lu is waiting for them on the other side, only to complain that the door is something else he needs to fix now (next to the speaker). Simian tells Big Chill that Lu needs to "chill" out, but Big Chill says no since he doesn't like freezing people. Simian takes things into his own hands and sends Lu over the bridge before running away, prompting Big Chill switch into Jetray to catch Lu just in time and they exchange notes.

Simian finally arrives at the central chamber where the crystal is and tries to take it, only to have a near deadly encounter with the tazer cannon defense systems. Ben transforms into Chromastone, rescues Simian, and takes the crystal. When the fortress loses power and emergency lighting kicks in, Simian wakes up and claims that they make a good team. However, Ben refuses him the crystal, as he is upset with how Simian was going to kill an innocent guard in cold blood back on the bridge. He tries to explain that there are more lives at steak on his home planet, but Ben still doesn't believe him since a real king can't go around murdering innocent people who stand in his way. Simian tells Ben how he's come to his sense, but Ben sees through his lies and a battle for the box Ben put the crystal inside ensues. In the midst of the battle, Ben discovers that Simian has been lying the whole time, and that the crystal is actually the power source for an intergalactic communications station. Ben, Gwen, and Kevin have been manipulated and sold out by an Arachnichimp con artist and a selfish mercenary hired by the Highbreed to steal the crystal to prevent Earth, through the Moon, from calling for help against the incoming invasion force.

Simian incapacitates Ben before he can transform into Humungousaur and leaves with the box. He fools Kevin into thinking Ben's right behind him and knocks Gwen aside, taking his ship and stranding the gang on the moon. However, they let Simian escape and Ben reveals to the gang that Lu's going to let the gang use his shuttle to get home, and how he knew Simian was lying; he initially claimed he had never heard of the DNAliens, but wound up blowing his own cover when he openly recognized the acidic ear cleaner. Ben also reveals that he still has the crystal on him, leading to Gwen asking him what Simian escaped with. Back on Earth, Simian makes the exchange with a Highbreed commander, only for things to get ugly when it opens the box only to find the ear cleaner instead of the crystal.

Noteworthy Events

Minor Events

Character Debuts



Aliens Used



Kevin: Craziest thing we've ever done. And that's saying a lot.
Gwen: Ben identifies with the prince. They've both had a lot of responsibility thrown at them, they're both young.
Kevin: They both get on my nerves.

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Goop: Figured I'd find you here. It's me, Ben! What are you doing?
Simian: I-I need some equipment.
Goop: So, you just decided to take it? That's called stealing!
Simian: Can't be helped.

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Ben: I'm not going alone. I told him I wouldn't go without you two.
Kevin: Great. So where's the fortress?
Ben: (looks up at the sky) On the moon.

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(Kevin, Ben, and Simian taking off spacesuits)
Kevin: Nice to be out of this monkey-suit. (looks at Simian) Uh... no offense.

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Simian: Ben, I think this guy needs to chill out, what do you think?
Big Chill: I think hate puns and I know I don't like to freeze people.

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Simian: Sorry, Ben. I'm leaving here, with the crystal.
Ben: We'll just see what Humungousaur has to say about that!
(Simian webs up the Omnitrix, using it to slam Ben into a wall)
Simian: I don't think Humungousaur has anything to say.

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Naming and Translations

Language Name Origin
French Mon Semblable My Kind
Hungarian Madarat Tollával Bird With Its Feather
Polish Małpi Książę The Monkey Prince
Portuguese (Br) Diga-me Com Quem Andas Tell Me Who Your Friends Are
Romanian Oameni din Aceeaşi Categorie People in the Same Category
Spanish (HA) Ayudando Al Enemigo Helping the Enemy
Spanish (Spain) Tal Para Cual Tit For Tat


Voice Actor Role(s)
Yuri Lowenthal Ben Tennyson
Ashley Johnson Gwen Tennyson
Greg Cipes Kevin Levin
Dee Bradley Baker Big Chill
Diedrich Bader Simian


  • The title of this episode comes from the saying "Birds of a feather flock together".


  • Ben again shows his martial arts skills, as the majority of the time he fought Simian, he was using hand-to-hand combat rather than transforming into an alien.
Ben 10: Alien Force Episodes
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