Upgrade

Upgrade (voiced by Tara Strong) is the 9th Alien to appear on the series. Upgrade is a Galvanic Mechamorph (mecha- meaning machine and -morph meaning transform) of the planet Galvan B, a formerly uninhabited moon orbiting Galvan Prime. It was said to be born when self-replicating nanotechnology bonded with Galvan B's mineral molecules. It is supposedly the result of some Galvan scientists' dumping of chemicals with self-replicating nanotechnology to that moon, probably by mistake.

Abilities
It has the ability to reshape itself, as it can turn to some sort of liquid at will. Galvanic mechamorph's can also strech their limbs about 20 to 40 feet depending on it's age. Its internal nanotechnology allows for Upgrade's primary ability to merge with and 'possess' any technology within reach by spreading over it like liquid, enhancing it far beyond its original design.

The size of the device is inconsequential. While merged with a device, Upgrade controls it as he would his own body. Even without a machine at hand, Upgrade can reconfigure his form around his eye in order to fire a plasma beam from it. Upgrade is also capable of forming simple constructs from plasma, such as spikes, and also partially posses a machine to enhance his lasers. He can phase through metal and technology.

Also, Upgrade can probably reform after being blasted and parts are torn, as shown by Bazel in "Vreedle,Vreedle".

Weakness
Upgrade's weakness is from its specialization: being technology-oriented, Upgrade cannot possess biological creatures (so Ben keeps his own voice when transformed), and sentient robots are harder for it to control.

He is also weak electicity being living metal as shown in Tourist Trap

Unusually, Ben keeps his human voice while transformed as Upgrade, likely due to the Galvanic Mechomorph issue of not being able to bond to anything organic in nature. This either means Ben's transformation is not complete or the Omnitrix is built this way.

Trivia

 * In the episode Pier Pressure of Alien Force, Ben mentions to Julie that he used to transform into a Galvanic Mechomorph after seeing Baz-L.