Prepare Simple Syrup: In a small saucepan, combine equal parts water and sugar. Heat over medium heat, stirring until the sugar dissolves. Remove from heat and let it cool.
In a blender, combine the frozen pineapple chunks, pineapple juice, white rum, fresh lime juice, and simple syrup. Blend until smooth and creamy.
Fill glasses with ice cubes and pour the pineapple cocktail over the ice.
