Prepare by getting out your lollipop tray or lining a baking sheet with parchment paper. Also, fill a large bowl with ice water and set it aside (you will need it later).
In a medium saucepan combine sugar, corn syrup, and water and heat over medium heat. Attach the candy thermometer to the inside of the pan (you want it to be touching the candy). Turn up the heat to medium-high and bring mixture to a boil, stirring until the sugar has dissolved.
While the mixture is boiling, wash down the sides of the saucepan with a small pastry brush dipped in water. You’ll want to wash down any sugar crystals that try to form on the sides of the pan.
Continue to boil until the thermometer reaches 310 degrees (this is the hard-crack stage). Immediately remove the pan from the heat and set into the bowl of ice water (don’t let any water get into the pan though!). Swirl it around a few times. Remove from the water. Add your food coloring and quickly stir in. Pour your candy mixture into your tray molds or onto your parchment paper in 1-2” circles. Immediately add in your sticks and eyeballs before the candy sets.
Notes
You can switch up the food coloring and make any color monsters you'd like!