is it normal for supervisors to nick your ideas and use them as theyre own?
How do u deal with a supervisor that just wont let u get on.

Cyanide in their coffee ?

Or maybe (more legally than the last suggestion!) you could spike their morning coffee to make them sleep the whole day, every day. That way you could get on with your stuff, whilst the supervisor snoozes away in the office.

Laxatives in their coffee ?

I say report them. I have had that happen to a fellow student with an evil prof. They did not report him and he continues to reep havoc in the department stealing ideas and having no original thought of his own. You must stop them, stop them now for the benefit of all studentkind.

I do agree if you have a major grievance and can show beyond all reasonable doubt that it's really your work, then you should say something. If you don't feel comfortable going to the head of the department, go to someone impartial such as any of the student support services.