Measure and prepare all ingredients. Divide popcorn into three bowls, tinting two with red and blue food coloring, and leaving one plain white.
Place a large saucepan over medium heat. Add sugar, corn syrup, and butter; stir with a silicone spatula until the mixture starts to melt and smoothens, about 3-4 minutes. Continue cooking until the mixture begins to bubble and reaches 240°F (soft ball stage) on a candy thermometer, approximately 5 minutes.
Remove the saucepan from heat and stir in vanilla extract. Quickly divide the hot syrup into three parts, tinting each with red or blue food coloring as desired, while the remaining remains uncolored.
Drizzle each flavored syrup over their respective popcorn bowls. Use the silicone spatula to gently toss and coat the popcorn evenly in each color, creating a visually distinct mixture for each.
Combine all three popcorn varieties into a large mixing bowl. Let the mixture cool slightly so the syrup sets slightly, then evenly portion and shape the popcorn into balls using clean hands or a scoop. Place each ball on parchment paper to cool and set, allowing the exterior to firm up and form a glossy, crunchy coating.
Once set, serve the popcorn balls as a colorful, crisp treat with a chewy interior, perfect for festive occasions or snacking.
