Crush the cookies in a food processor until very fine (you can also place them in a ziploc bag and use a rolling pin to crush them.)
Combine the crushed cookies, sugar and melted butter and mix well. Press into a 9inch pie pan and bake at 450 for about 5-7 minutes.
In a bowl combine the egg yolk and creme fraiche together.
Warm the milk in a small pan on the stove and add the chopped chocolate. Stir until the chocolate has melted and is smooth.
Add the creme fraiche mixture to the chocolate and mix well.
Pour the mixture into the cookie crust and bake at 325 for about 30-35 minutes. The top will still be slightly jiggly but will firm up as it cools. (Quicker in the fridge and easier to slice)
Place the gummy rings in the pie to form gravestones. Decorate the pie with assorted gummy worms, bears, spider etc to look like a graveyard.