Prepare cake mix according to package directions. Spread batter into parchment paper–lined 13- x 9-inch baking pan. Sprinkle half of the chopped SNICKERS Fun Size over half of the batter; smooth top. Bake according to package directions or until tester inserted in center comes out clean. Let cool completely on rack.
Crumble portion of the cake with SNICKERS Fun Size (you should have 3 cups). Reserve remaining cake for another use.
In large bowl, combine cake crumbles, cream cheese and remaining chopped SNICKERS Fun Size until dough starts to form. Shape into twelve 1 1/2-inch balls; transfer to parchment paper–lined baking sheet. Using thumb and fingertips, shape each ball into helmet shape. Freeze for about 15 minutes or until firm.
Dip 1/2-inch of the tip of each cake pop stick in icing; push tip halfway into each helmet. Freeze for about 15 minutes or until firm.
Dip 6 helmets into melted white candy melts bowl, letting excess drip back into bowl. Stand cake pop helmets in block of Styrofoam. Transfer remaining melted white chocolate melts into piping bag for decorating. Repeat with remaining helmets and melted milk chocolate candy melts.
Decorate each helmet with pretzel piece, and dragées to resemble face mask part of the helmet. Freeze for 10 to 15 minutes or until candy melts are set.
Using reserved melted white chocolate melts, pipe numbers on brown helmets; using black icing, pipe numbers on white helmets. Let stand for 5 to 10 minutes or until icing and chocolate are set.