If you want to add a cereal rim to your glass, do this first. Spread frosting or marshmallow fluff around the rim of the glass. Then place marshmallows onto the frosting and set aside.
Pour milk into a bowl with the fruity pebbles and let sit for 30 minutes.
Strain milk and discard cereal.
Pour milk and ice cream into blender and blend until smooth and creamy.
Pour into glasses and top with whipped cream and cereal!