Line a 12-inch pizza pan with foil. Grease foil and set aside. Remove and throw away all unpopped kernels from the popped popcorn. Grease 2 13x9x2-inch or larger baking pans. Divide popcorn evenly between the two pans.
In a large saucepan combine corn syrup and sugar. Heat over medium-high heat until boiling, stirring constantly. Remove from heat; stir in marshmallow creme, butter, and vanilla. Pour half of this mixture (about 2 cups) into another saucepan. Tint each portion with desired food coloring. Add marshmallow mixture to popcorn (keeping colors separate). Stir to coat evenly. Cool until popcorn can be handled easily, about 10 minutes.
With greased hands, press one color of the popcorn mixture into prepared pizza pan. Shape the remaining popcorn mixture into a 8-inch cone about 6-inches in diameter. Top base with cone shape. Decorate with chocolate pieces and fruit leather. Makes one witch's hat.