  Grey Matter is a Galvan from the planet Galvan Prime. He is Ben's 5th transformation who appeared first in Washington B.C.
Appearance[]
Grey Matter is a very small alien. Its unknown how small he is but he is the smallest alien in his galaxy. He is all greenish and looks like a martian. He is wearing the same shirt that normal Ben is wearing and the Omnitrix symbol is on his back.
Abillities[]
Being very small grey matter is able to go through the smallest of spaces giving him an advantage. He is also the smartest being in 5 galaxies so he can create almost anything or destroy anything.
Ben 10[]
Grey Matters debut
He first appeared in the episode Washington B.C. where he is looking for the gold Sumo Slammers card in the M-Mart. After he makes a mess he leaves his cousin Gwen getting in trouble.
Appearances[]
Ben 10[]
Transformation[]
thumb|394px|left
Gallery[]
