Preheat oven to 325 degrees and spray an 8x8 baking dish with non-stick cooking spray. Whisk eggs in a medium bowl. Add oil and water and whisk until well blended. Add dry brownie mix and stir until well combined.
Pour batter into prepared pan and spread evenly. Bake for 19-22 minutes or until toothpick inserted into the center comes out clean. Once cooled, cut brownies into one inch squares.
Alternate threading brownie squares, berries and marshmallows onto wooden skewers. Refrigerate until ready to serve.