http://awesomerecipes101.blogspot.com/2009/11/chocolate-mousse-pie.html
In a heavy saucepan place the candy bar, marshmallows and milk. Cook over low heat, stirring constantly until chocolate is melted and mixture is smooth.
Remove from heat and let cool.
Fold in cool whip until well blended.
Pour into crust.
Refrigerate for at least 3 hours or until set up.