Serious question about hair color?

I have shoulder length hair, really thick, and its not short enough to just use one bottle of hair color. I happen to have one box of burgundy, and one box of dark blonde color (two different brands) I was wondering 1. what would happen if I mixed in some of the blond with the burgundy 2. would the end result look really stupid. I wouldn't really try this unless I did a test strand first to see what happens, but I just wanted an opinion on what you think would happen.