• Combine popcorn and pretzels in a large bowl. Set aside.

To prepare the caramel

• In a medium saucepan, bring sugar, ½ teaspoon salt, and water to a boil over medium-high heat.
• Boil, undisturbed, until mixture is yellow in color, for about 8-12 minutes.
• Remove pan from heat and slowly pour in the heavy cream. Be careful because the mixture will bubble up. Stir until smooth.
• Add vanilla extract, marshmallows, and drop of red food coloring into the pan.
• In a separate bowl add some of the marshmallows, add a drop of blue food coloring into the pan.
• Stir until marshmallows are completely melted and the mixture is smooth.
• Pour caramel mixture over popcorn and pretzels and gently stir with a rubber spatula until popcorn is well coated.
• Stir in the M&M's. Transfer mixture to a large baking sheet and sprinkle with sea salt. Let cool completely.