In large microwavable bowl, place cereals and crackers. Mix until combined.
In small microwavable bowl, microwave butter uncovered on High 30 to 60 seconds or until melted. Stir in dry ranch dressing mix until no clumps remain.
Pour butter mixture evenly over cereal mixture. Carefully stir until evenly coated. Microwave uncovered on High 4 minutes, stirring every minute.
Stir in cheese balls. Cool 5 minutes before serving. Serve immediately, or store in airtight container.