Melted Wicked Witch Punch

Mix water, sugar, and gelatin mix in a large saucepan and bring to a boil; reduce heat to medium and cook at a boil, whisking frequently, until gelatin and sugar have dissolved, about 3 minutes. Stir pineapple juice, orange juice, and lemon juice into gelatin mixture and transfer into resealable plastic bags. Place in freezer until slushy, about 4 hours.

Pour mixture into a large punch bowl and stir in lemon-lime soda; float a black plastic witch hat atop the punch.