In a bowl, mix sugar and peanut butter. Add water.
Microwave for about 30 seconds. Then stir well.
It should be slightly runny. Set aside while you prepare molds.
Melt chocolate according to package instructions.
Place a couple of spoonfuls into frog mold. Using a brush that you have reserved for food use only, work the chocolate into the mold.
Place into the refrigerator for about 10 minutes.
Remove molds from the refrigerator. Fill to nearly the top with peanut butter filling.
Reserve a small bit of room to cover the peanut butter mixture with chocolate.
Place in refrigerator again. Allow to chill completely before removing your frogs onto a serving plate.