Open plastic Easter eggs on a baking sheet or work surface and mist the insides with oil.
In a microwave-safe container, microwave the margarine and Fluff for 1 minute. Stir. Repeat for another minute. Stir. Repeat for a third minute. Stir. Pour the glaze over the Rice Krispies and mix until combined.
Pack each side of the eggs with the cereal mixture, leaving a hollow in each. In each hollow, add a pinch of cookie and chocolate bark. Cover up the filling with more cereal mixture until you reach the rim. Snap each egg closed and let them set, undisturbed, for at least an hour or as long as overnight.
Reserve any remaining crushed bark and cookie crumbs.
Unhinge the plastic eggs and remove the treats. Roll the finished eggs in the remaining crumbles of bark and cookies before serving.
