Place marshmallows in a microwave safe bowl and heat until softened. I would suggest heating for a few seconds at a time until all of the marshmallows are soft.
In a bowl combine the cream cheese, powder sugar, vanilla and softened marshmallow or marshmallow fluff. You may want to use a stand mixer, food processor or hand mixer to make this process easier.
Put your mixture into the graham cracker crust.
Place the Hershey bars in a microwave safe bowl and melt the chocolate. Again, I would recommend setting your microwave for 10-20 seconds at a time and stir frequently until melted.
Pour the melted chocolate over the cheesecake filling, reserving a little for garnish.
Sprinkle mini marshmallows on top of chocolate.
Using a spoon, drizzle the remaining melted chocolate over the mini marshmallows.