Cake Mix Monster Cookies

1 box yellow cake mix
1/2 C packed brown sugar
3/4 C butter or margarine, softened
1/2 C creamy peanut butter
2 T water
1 egg
3 C quick-cooking oats
1 C candy-coated milk chocolate candies (M & M's)
1 C semisweet chocolate chips

Preheat oven to 350 degrees. In a large bowl, mix cake mix, brown sugar, butter or margarine, peanut butter, water, and egg with electric mixer on medium speed. Stir in oats until combined, then stir in candies and chocolate chips. Using a large cookie scoop, drop dough two inches apart on ungreased cookie sheet. Bake 14 to 15 minutes or until edges are just golden brown. Cool five minutes on cookie sheet. Remove to cooling rack to cool completely.  Note: If making smaller cookies, bake for 12 to 13 minutes.