The phrase "Ты кто такой" supposedly means "Who are you?". I have a few questions.
Does the phrase "Ты кто?" have a meaning? If so, how does it differ from "Ты кто такой" ?
Are there other question forms with "такой" on the end? Is the "такой" necessary to be grammatically correct, and if not, what extra meaning does in convey?
How can we explain the meaning of this phrase, given that "такой" means "such" ?