Bring some water to a boil in the lower part of a double boiler
the chocolate bar in the upper part, stirring occasionally, to ensure smooth, even melting. While that's going, cut the cereal bar into four pieces. When the chocolate
is melted and gooey, roll the cereal-bar pieces in it to evenly coat on all sides and place them on wax paper. Let them cool in the freezer for about 10 minutes.
While the pieces are cooling, crush a handful of the cereal with a mortar and pestle or a food processor. Sprinkle the crumbled cereal over the dummies.