I heard this sentence in a movie dialogue:
You never rolled?
Is the complete form of the given sentence:
Have you never rolled?
Assuming the context here was rolling a cigarette or a joint, the response "You never rolled?" is as explained - the responder expresses surprise that the addressee has never rolled (a joint,say). Though it would be less ambiguous if phrased thus - "You've never rolled?" (Of course the 'Have you never..' form is most formal)
If you presented the question with no context, "You never rolled?" could equally mean something along the lines of "We used to roll down the hillock in our childhood. What? You never rolled?" Here the usage of roll is that the person is the thing that is rolling, as opposed doing the rolling (to a cigarette, say)
Is just an informal way of turning a statement into a question in order to reassure oneself about the statement in question.
Therefore, this is how the question may arise: