When someone tacks the word what onto the end of a question, it should stand alone as
its own question.
...Was it given to you as a gift? What?
...Were you there alone? with someone? What?
...Did the company have benefits? profit sharing? What?
When someone turns a "what" question around, punctuate it just as you would the
question in regular word order. This is just "bad grammar/good punctuation."
...What was it? A Toyota?
...It was what? A Toyota?
...What was her name?
...Her name was what?
Happy punctuating!
Margie