Preheat oven to 350 degrees F (175 degrees C). Coat an 11x15-inch baking pan with cooking spray.
Empty brownie mix into a large bowl. Add vegetable oil, eggs, and water; stir with a wooden spoon until batter is well blended. Pour batter into the prepared baking pan.
Bake in the preheated oven until a toothpick inserted 1 inch from the edge of the pan comes out clean, 35 to 40 minutes. Let cool completely, about 30 minutes.
Combine chocolate chips and heavy cream in a microwave-safe bowl. Heat in the microwave in 30-second intervals, stirring after each interval, until melted and smooth. Cool, about 5 minutes.
Break brownies into pieces and place in a large bowl. Pour ganache evenly over brownie pieces; mix thoroughly.
Line a jelly roll pan with parchment paper. Press brownie mixture evenly into the pan. Freeze until firm, about 30 minutes.
Pour confectioners' coating into a microwave-safe bowl. Microwave at 50 percent power for 1 minute; stir thoroughly. Continue to microwave and stir at 30-second intervals until smooth and completely melted, 1 to 2 minutes more.
Roll brownie mixture into balls; insert a lollipop stick halfway into each. Dip balls one at a time into melted confectioners' coating to form a thin, even coating, letting the excess drip off. Stick into a styrofoam block; let stand until coating hardens, about 10 minutes.