In a food processor add yogurt, frozen strawberries and dragon fruit and blend until smooth. Enlarged the holes of the two part skull mold using scissors so that the holes are about 1-inch in diameter. Assemble the 2-part skull mold and pour yogurt mixture into skull molds and freeze overnight. Melt hard candies in a microwave safe liquid measuring cup. Microwave on half power for about 2-2½ minutes until melted. Adjust time as needed. Pour into molds and let cool completely. Remove skull candies from the molds and set aside. Remove the stems off of 8 apples. Heat one end of a metal skewer by holding it over a flame and press it into the top of the skull to melt it a bit and then stick the apple stem in it. Repeat with the remaining skulls and stems working one at a time. In a large bowl, add heavy whipping cream, powdered sugar, vanilla and food coloring and beat until fluffy.
Optional: Cut out red dragon fruit crossbones with a mini bone cookie cutter.
Assemble Sundae: Place dragon fruit crossbones down first. Place skull scoops next. Drizzle with strawberry topping, whipped cream and top with a candy skull cherry and sprinkles. Enjoy!