In a large microwave-safe bowl, add the marshmallows, butter, water, and the Jell-O/pudding mix (if using).
16 oz mini marshmallows, 4 Tbsp salted butter , 2 Tbsp water, 1 box (3oz) Jell-O or (3.4 oz) instant pudding mix, powder only (if desired)
Microwave for 30 seconds and then stir. Repeat once more, until the marshmallows are completely melted.
In an extra-large bowl, fold together the popped popcorn and marshmallow mixture until well combined.
14 cups (84g) popped popcorn
Using hands that are slightly damp with water, portion out the popcorn and gently press into balls and place on parchment paper to set up.
Store in an airtight container for up to 3 days.