Preheat the oven to 350F. Butter a 13x9-inch cake pan.
In a large bowl, whisk together cake mix, water, oil, and eggs until combined. Pour into the cake pan.
Bake according to package directions. Cool completely.
Line a small baking sheet or plate with wax or parchment paper.
Crumble cooled cake into a large bowl. Add frosting and stir with a wooden spoon or beat on low speed until mixture resembles wet sand, but is not smooth, about 30 seconds if using an electric mixer. Scoop 1 tablespoon of the cake mixture and roll into 1-inch balls. Place on the lined plate. Refrigerate for at least 4 hours or freeze for 30 minutes.
Melt candy or chocolate wafers according to the package instructions and place in a 2-cup liquid measuring cup or tall drinking glass. Pull a few cake balls out, leaving the others in the fridge as you work so they stay cold (keeping them cold helps the coating set quickly). Dip the tip of a lollipop stick in the melted chocolate and insert about halfway into a cake ball. Dip the cake ball into the chocolate making sure to cover the base where the stick and cake ball meet,and turn to coat. Remove and gently tap on the side of the cup to let excess coating drip off.
Decorate with sprinkles if desired. Place upright in a styrofoam block or cardboard box. Let stand until the coating is set. Cake pops should be stored in the fridge for up to 1 week.