Birds of a Feather

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

Plot
Ben, Gwen and Kevin are surrounded by a large amount of DNAliens near a forest. Ben uses Spidermonkey to face 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.

Ben as Goop finds Simian again, this time at a factory stealing a piece of scientific equipment. After Ben scolds Simian of being a thief, he takes him to a place. There, Simian reveals himself to be the prince of Arachnichimps. Simian needs help in retrieving a crystal which is the symbol of monarchy on his planet. The crystal is being kept in a base on the moon. Ben offers his help but Gwen and Kevin are skeptical. But they are swayed by Ben's argument and decide to go to the moon with Ben and Simian, even though they still don't trust the 'Spidermonkey'.

In the midst of the battle, Ben discovers that Simian has been lying, and that the crystal is actually powering an intergalactic communications station. By stealing it, Simian will prevent the Earth through the Moon from calling for help against the Highbreed Invasion. As Ben faces off against Simian for the crystal, he tricks Simian into stealing the worthless acid dispenser instead, resulting in Simian having a very unpleasant encounter with the Highbreed that employed him, and seemingly gets killed off-screen.

Characters

 * Ben Tennyson
 * Gwen Tennyson
 * Kevin Levin
 * Lu

Villains

 * Simian
 * Highbreed

Aliens Used

 * Spidermonkey
 * Goop
 * Big Chill
 * Jetray
 * Chromastone

Allusions

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

Trivia

 * Simian mentions his and Spidermonkey's species by name.
 * At the end, the Highbreed's red marks on his face actually seem like eyes in this episode, where others are not.
 * It is revealed that Spidermonkey's species has a acute sense of hearing.
 * When Ben turns into Jetray, he didn't say his name.
 * It is revealed that Big Chill can fly without wings and that he can freeze with his hands, which also happens in Single Handed.
 * 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.
 * Spidermonkey has a new transformation sequence, that is a lot different from the old sequence.
 * Simian called his planet Arachna.
 * This episode is the third year celebration of Ben 10.
 * It was believed that the Highbreed uses the acid to kill Simian, because of the melting sound but it seems that the Highbreed changes his mind and just imprisons him since he re-appears in Simian Says and stated he escaped from a spaceship.