One of those actors you've probably seen in any number of things, but is still highly underrated and unrecognizable. Some of his work includes:

Normally playing a psychotic or killer of some sort, Brad Dourif is one of the scariest actors I am familiar with. I read an article once likening his performance in the X-Files to Anthony Hopkins in The Silence of the Lambs, and I would tend to agree.

Dourif will be playing Grima Wormtongue in the upcoming Lord of the Rings series.

(Some information gathered from