Looking for General Grievous Halloween costume

Adam wants to be General Grievous for Halloween. Does anybody know where to purchase a General Grievous costume? Even a mask would be a big help. A. is willing to try to make a costume, but it will be fiendishly difficult.

(If you're wondering why I give my wife more anonymity than my son, it's because the minute I picked the LJ name "patoadam" any hope of keeping Adam anonymous went down the tubes. Other ways of distinguishing them, such as A1 and A2 or "big A" and "little A", seem even worse.)

In other news, Adam has started first grade and he likes his teacher. We are so relieved. Adam's best friend, who is older than Adam and in second grade now, had Adam's teacher last year, and all the friend's mother could talk about is what a wonderfully strict disciplinarian the teacher is and what a good job she does of making the children behave. We don't want that. We want Adam to enjoy school. So far, he is enjoying first grade.

Anything else I might have said about Adam starting first grade was said much more eloquently by artbeco here and by trystel.