Place popcorn in a large heat-proof bowl; set aside. In a saucepan over medium heat, mix together remaining ingredients except worm candies. Bring to boil. Stir mixture until it reaches the thread stage, or 230 to 233 degrees on a candy thermometer. Pour over popcorn; mix well and form into balls with well-buttered hands. Poke a hole with finger and add gummy worms. Reform ball as needed. Wrap balls in squares of wax paper.