In a saucepan, combine the sugar and corn syrup over medium-high heat until it comes to a full boil. Remove from heat and add the peanut butter, stirring until smooth and incorporated.
In a large bowl, mix the corn flakes and the peanut butter mixture together, gently stirring very well until all of the cereal is coated.
Drop spoonfuls of the cornflake mixture onto wax paper.
Heat the chocolate in the microwave, stirring every 30 seconds, until melted and smooth. Drizzle over cornflake clusters and let cool. Serve when they have cooled.