To make candy cup, place baking cup in standard muffin pan and paint inside with brush and melted light cocoa candy; refrigerate to set and carefully remove paper.
To make base for bubbling brew, place medium round cutter on cookie sheet and fill with green-tinted melted candy; freeze until set. Unmold candy base and top with mini marshmallows; cover with melted candy; let set.
Fill candy cup with candy corn and cover with candy base. Use spatula striped orange and yellow royal icing in bag fitted with tip 352 to pipe pull-out flames; position pretzel sticks. Attach ghost on top with melted candy.