Place the chopped semi-sweet chocolate in a medium bowl. Pour the cream into a small saucepan and add the light corn syrup and a pinch of salt. Place the pan over medium-high heat and bring it to a simmer, heating it until bubbles appear along the sides of the pan, but don't bring it to a boil.
Pour the hot cream over the chopped chocolate and let it sit for one minute to soften the chocolate. Gently whisk together the chocolate and cream until melted, shiny, and smooth. Add the butter and whisk it in until combined.
Press a layer of cling wrap on top of the chocolate ganache. Refrigerate the bowl for 1-2 hours, checking the texture every 30 minutes, until it's firm enough to roll but not rock-hard. Roll the truffles into 32 small balls, about 1/2-inch to 3/4-inch wide. If they get sticky, dust your palms with cocoa powder and roll the balls between your palms to make them round. Place the truffles on a baking sheet lined with parchment or waxed paper. Refrigerate the tray of truffles.
Crumble the brownies into a large bowl. Add 1/4 cup of chocolate frosting, and stir them together. Depending on how moist your brownies are, you may need to add additional frosting to get the brownie mixture to be a soft, moist consistency. When you squeeze it between your hands, it should easily hold a ball shape, but not be too wet or greasy.
Scoop a spoonful of brownie mixture and press it around a chocolate truffle. Roll it between your palms, and place it back on the baking sheet. Repeat until all of the truffles are covered with a brownie layer. Refrigerate the tray the brownie truffles are firm.
Melt the chocolate candy coating in a microwave-safe bowl in 30-second intervals, stirring after every 30 seconds until melted and smooth. Use dipping tools or forks to dip a truffle into the chocolate, then remove it from the bowl and let excess drip back into the bowl. Place the truffle on the prepared baking sheet, and while the chocolate is still wet, sprinkle the top with a pinch of disco dust. Repeat until all of the truffles have been dipped and decorated.
Store Disco Truffles in an airtight container in the refrigerator for up to a week. For the best taste and texture, bring them to room temperature before serving.