Brainstorm

Brainstorm is a Cerebrocrustacean from the planet Encephalonus IV.

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

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 (however this was merely because the Omnitrix was shaken too much, thus causing the dial to change, so this was not a general accidental transformation).

Appearance
Brainstorm has a crab like appearance. He's has 2 claws and 3 pairs of legs. The Ultimatrix is on his Cephalothorax. He can open his skull plates at will to reveal his brain. Also, he speaks with a British accent and enhances Ben's vocabulary.

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 also has the power to levitate himself as well as other people and create electricity from his pincers without needing to open his skull plates, he can also cause a storm just by thinking. He may be extra durable due to his shell. Brainstorm is also thumb|right|266px|Brainstorm transformationshown to be adept at back flips, as shown in "Good Copy, Bad Copy", and somersaults as shown in "Single-Handed ". He also has the ability to control machinery like in Escape from Aggregor.In a unique use of his electricity brainstorm is capable of rewriting electronics by making contact with his electricity.He has also shown to be able to control various aspects of his electricity ranging from a pushing,to shocking,to protective coatings(on other people). He can also control the color of it.

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 and made it hard for him to concentrate (and suggested that concentration is required for him to use his powers). Also the species tends to be egotistical 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. Brainstorm does not have good movement with his crab legs. In Fused, it is discovered that Brainstorm's electro blasts can be grounded and a weak spot is at his brain, when struck he experiences excruciating and unbearable mental pain, which is probably why the species developed the casing.

Alien Force
Ben first transformed into Brainstorm during the episode Pier Pressure when he had to fight a Galvanic Mechamorph. He later appeared in Good Copy, Bad Copy to fight Albedo.

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 make it attack Animo.He has the same appearance from Alien Force. He reappeared in Fused, where he fought and was defeated by Aggregor because his weapon withstands electrical powers. He finally makes another appearance in the episode Eye of the Beholder, where he is trying to free Baz-El. He is also seen being able to stop enemies attacks when one of the aliens shot him but Brainstorm was able to use his abilities to stop the laser beam and knock out the alien.

Alien Force

 * Pier Pressure (first appearance)
 * 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

 * Fame (video footage)
 * Escape From Aggregor (first re-appearance)
 * Fused
 * Eye of the Beholder

Naming and Translations

 * Italian: Cervellotico/mastermind
 * Norwegian: Brainstorm
 * Portuguese: Artrópode/Arthropod
 * Bulgarian: Мозъчен щурм / Brainrush
 * Romanian: Encefal/encephalon, or brain
 * Croatian: Intelektus (based on the word Intelect)
 * Deutsch: Superhirn/Super Brain
 * Dutch: Brainstorm
 * Spanish: Cerebrón (Brain)
 * Hungarian: Észlény
 * Polish: Łebkrab (Brain and crab)
 * Serbian: Intelektus
 * Turkish:Beyin Fırtınası

Trivia

 * Like Lodestar, he also has a mouth that never moves except to show emotion but in Good Copy, Bad Copy, it almost moves, in War of the Worlds: Part 2, it opened when he vomited, and in Vilgax Attacks, it moves and closes depending on his motion.
 * He has only had two appearances in a video game, while the other original 10 have been in 3 appearances.
 * 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's species' name has the word 'crustacean' in it, because they look like crabs.
 * In the story Ship Shape, when Brainstorm said 'Er, my bad.' the belt on his suit is grey instead of black.