Grease candy molds with non-stick cooking spray or line a baking sheet with parchment paper.
In a saucepan, combine sugar, corn syrup, cannabutter, and water. Use medium heat to cook while stirring constantly, until the sugar dissolves.
Once the sugar has dissolved, stop stirring and let the mixture come to a boil by doing all this keep using a candy thermometer to monitor the temperature.
When the temperature reaches 300°F, add the Jolly Rancher candies and stir until melted.
Remove from heat and pour into prepared molds or onto prepared baking sheet.
Let the candies cool and harden completely before removing them from the molds or breaking them into pieces.