I was wondering if in a flash would be a good stage trick if not what would.

NO!!! If you want to use cards, starry eyed suprise would be pretty tight or just any card manipulations. Besides that look in the stage magic section!!

Which "In A Flash" do you mean ?

There is some Jay Sankey thing called "In A Flash" which is a card trick, completely inappropriate for stage magic, but there is also a box magic trick called "In A Flash" that can be used to produce doves or a rabbit, etc. .

The box trick looks like this : In a Flash

A box with an open front is shown empty. Instantly a rabbit or a couple of doves appears in the box. Is that the one you mean ?