Scoop popcorn into a large bowl, making sure to remove uncooked kernels.
In a saucepan over medium heat, combine corn syrup, confectioners' sugar, marshmallows, butter, water and vanilla extract. Cook and stir until mixture reaches soft ball stage around 240F.
Pour hot sugar mixture over popcorn.
Quickly stir to coat the popcorn and stir in the marshmallows.
Grease hands or popcorn baller. Quickly shape the popcorn mixture into balls before it cools.
Recipe by Sugar, Spice and Family Life at https://sugarspiceandfamilylife.com/2017/03/lucky-charms-popcorn-balls-recipe.html