Boil a little water in a pan. Add mango flavour jelly powder in the water. Whisk gently so that the granules in the jelly powder get completely dissolved in the water. Pour this water to a bowl. Refrigerate it to make the jelly. Add this jelly to a mixie jar. Add milk mango pulp, ice cream, a little chocolate syrup and powdered sugar. Blend them well to prepare the milkshake. Garnish a glass with chocolate syrup. Pour the milkshake into the glass. Garnish it with a mango slice and candies.