Preheat oven to 350F, and line a 9x13 pan with parchment paper.

Empty the contents of the brownie mix in a mixing bowl, then pour in the whole can of soda. It will fizz and bubble alot, but it's okay! Stir well until there are no more lumps. The batter will be REALLY, really liquid, but don't panic! It's supposed to be like that.

Pour batter into prepared pan, and bake for about 25-30 minutes.

Check on them when you start to smell them, you definitely don't want these to burn! They will not form a crispy "skin" like regular brownies because of the carbonation, so they will look a little funny. They taste delicious though!