Stir gelatin mix and sugar into boiling water until completely dissolved. Add lemonade and pineapple juice; mix well. Blend in cold water. Pour mixture into gallon-size plastic freezer bags; freeze overnight. Remove bags from the freezer 2 hours before serving; knead slightly while in bag. Place mixture in a punch bowl, adding desired amount of soda.
To make the floating hand, rinse out a disposable plastic glove. Fill with water that has been colored with green food coloring. Freeze until firm. Remove glove by running cold water over the glove. Cut away some of the plastic glove and gently remove hand. Float ice hand in punch bowl.