Greymatter

Grey Matter is the Omnitrix's DNA sample of a Galvan from the planet Galvan Prime. He is chronologically the seventh Alien Ben transformed into on screen.

Appearance
Grey Matter is a grey skinned, frog-like, bipedal alien that is only four inches tall with large green eyes, which have rectangular pupils. He wears a white jumpsuit with a black stripe going down it, and the omnitrix symbol on his chest and Grey's pendent (Rave Stone) on his neck.

Powers and Abilities
Grey Matter's small size belies his great calculative and technical intellect. He can create complicated machines from spare parts, understand the function of any device at a glance, and make sophisticated repairs to complex machines, (such as a warp-drive engine). Grey Matter's intellect serves as a problem solver and analytical help in difficult situations. This allows Grey Matter to think more strategically when brute force is inefficient.

Grey Matter can sometimes manipulate living things by stimulating certain parts of their nervous system, if such beings can be controlled by external stimuli.

Grey Matter's size allows him to squeeze into small spaces and can climb walls due to tiny suction cups on his skin. He also has sharp teeth and his slimy skin makes him difficult to grab.

Grey Matter appears to be stronger than he looks, as he was strong enough to move a cleaner's bucket with mops in it in as shown by his prime counterpart in Ultimate Weapon, and in So Long, and Thanks for All the Smoothies, he was able to break a coolant pipe to freeze the Vreedle Brothers.

According to Derrick J. Wyatt(Original Author), Grey Matter is amphibious and has gills.

Grey Matter has a long prehensile tongue, owing to his insectivore nature. As a Galvan, he also possesses a 'pre-brain' which deals with all basic bodily functions.

Weakness
Grey Matter's small size makes him unsuitable for physical battle, so he must outsmart his enemies in a fight. Animals like dogs and cats can be a problem, as they may see Grey Matter as a chew toy or food to them.

Trivia

 * Ben/Lucca turns into Graymatter numerous times off screen