Pour cereal into a large microwaveable bowl. Line a cookie sheet with waxed paper, foil, parchment paper, or a silicone mat. Set aside.
In a small microwaveable bowl, heat brown sugar, butter, and corn syrup for 1 to 2 minutes on high, stirring after 1 minute until smooth and butter is completely melted.
Pour mixture over cereal and stir until coated evenly.
Place cereal in microwave and heat on high for 3 minutes, stirring after every minute.
Spread cereal onto the cookie sheet and even out. Allow to cool for 10 minutes and then break into bite-size pieces.
After it is cool to the touch, sprinkle mini Reese's and marshmallows over the top.
In a small microwaveable bowl, heat caramel bits and heavy cream for 1 minute and then stir until smooth. Drizzle over cereal.
Repeat with both the milk chocolate chips and white chocolate chips.
While the caramel and chocolate is still wet, sprinkle with salt.
Refrigerate until the chocolate is set and then break apart once again.