All you need to make the hats is:
Sugar Ice cream cones (pointy ones)
Chocolate frosting for the "glue"
Reese's pieces for the band on the witches hat
Store bought chocolate cookies for the brim of the hat.
Chocolate chips, melted
Ziploc bags for piping icing
Paint melted chocolate onto ice cream cones. Let cool and harden.
Place cone on top of chocolate cookie
Place a couple tablespoons of icing in Ziploc bag and cut small hole in corner of bag
Pipe the icing like "glue" around the bottom of the cone to attach it to the cookie
Pipe a small line of chocolate above the bottom of the cone to attach the Reese's pieces to the hat