Brainstorm

Brainstorm is a Cerebrocrustacean alien from the planet Encephalonus IV.

Ben first transformed into Brainstorm during the episode Pier Pressure when he had to fight a Galvanic Mechomorph.

Ben first selected to transform into Jetray but it switched to Brainstorm after the pier shook, which makes Brainstorm the first accidental transformation in the series. Brainstorm is also the only alien in Alien Force to not have his name shouted out, as Ben had to think about it first, as a first opportunity to show off his superior intellect.

Abilities
Brainstorm has the ability to control electrical energy and project force fields around himself and others through thought, accomplished by opening the exoskeleton plates on his skull. He is extremely intelligent but it is never revealed if he can rival Galvans (although, it has been hinted at in the Season 2 finale, when Azmuth and Brainstorm argue over who is more intellgent). He also has the power to levitate, and create electricity from his pincers without needing to open his skullplates as well. He can also levitate other people or things. He may be extra durable due to his shell. Brainstorm is also shown to be adept at backflips, as shown in "Good Copy, Bad Copy" and somersaults as shown in "Single-handed."

Weaknesses
In the episode, Good Copy, Bad Copy, Albedo turned into Echo Echo and Ben turned into Brainstorm. Echo Echo's sonic blasts gave Brainstorm a headache. Also the species tends to be egomaniacal which makes them forget how to do simple things as seen in Vengeance of Vilgax where Brainstorm forgot to capture a wild Spidermonkey due to its cocky attitude. They also tend to use large, scientific or intelligent terms that may not be understood by those they're talking to.

Sometimes, because of talking too much, he forgets that he's in the middle of a fight. It does not have good movement with its crab legs. In Fused, it is discovered that Brainstorm's electro blasts can be grounded and a weak spot is at it's brain,when struck he experiences excrutioating and unbarable mental pain,which is probebly why the species developped the caseing.thumb|right|200px

Ultimate Alien
Brainstorm reappeared in the Ben 10: Ultimate Alien episode, Escape From Aggregor, facing the yeti controlled by Dr. Animo. He is able to turn the yeti against Animo by re-wiring the mind-control device on him and makes it attack him and he has the same appearance from alien force. He reappeared in Fused, where he fought and was defeated by Aggregor.

Alien Force

 * Pier Pressure
 * What Are Little Girls Made Of?
 * Good Copy, Bad Copy
 * Voided 
 * War of the Worlds: Part 2
 * Vengeance of Vilgax: Part 2
 * Inferno
 * Single-Handed

Ultimate Alien

 * Escape From Aggregor
 * Fused

Naming and Translations

 * Italian: Cervellotico / mastermind
 * Norwegian: Brainstorm
 * Brazilian: Artrópode / Arthropods
 * Bulgarian: Мозъчен щурм / Brainrush
 * Romanian: Encefal/encephalon, or brain
 * Polish:Łebkrab
 * Croatian: Intelektos (based on the word Intelect)
 * Deutsch: Superhirn/Super Brain
 * Spanish: Cerebrón (Big Brain)

Trivia

 * When Ben is Brainstorm, he speaks with a distinct British accent.
 * He is the only alien shown to barf, as seen in War of the Worlds: Part 2 (and if you were looking very closely, you could partly see his mouth open, and his shell pops opens a little and sparks fly out).
 * Like Lodestar, he also have a mouth that never moves except to show emotion but in Good Copy, Bad Copy, it almost moves.
 * Normally, the Omnitrix/Ultimatrix, in the current green style, taps into Ben's subconscious and uses that to name the alien, shouting it upon transformation. With Brainstorm though, it seems he has no subconscious, thus having to think for a name, Or maybe this is because he became smart enough that the Omnitrix's AI thinks that he can think up his own name.
 * Unlike Benvicktor and Buzzshock his lightning is not green.
 * Brainstorm is obviously the replacement of Grey Matter(small size and high intellect), Benvicktor(Intelligents and Electrokineses), and Buzzshock(Electrical powers). Which is why he's so smart. Grey matter's species is the Smartest of them all and always has been as to where Benvictor's species is 3rd smartest and was 2nd. He's smaller than his other aliens because of Grey Matter alone and Electricity related powers is from Benvicktor and Buzzshock.