While driving clunking, revved on its own and black exhaust smoke

So I was driving home and all of a sudden the truck started making a clunking on acceleration and then just revved all the way up on its own, loads of black smoke came out of the exhaust and when I pulled over I turned it off. It will not start again now and I have spoken to a mechanic and he said it sounds like the turbo? What made the turbo do this? And will it just do it again if I buy a new turbo? Help please.