Divide pineapple chunks into about 8 oz. portions and freeze for at least 3 hours. (A whole pineapple will give you 3-4 8 oz. portions.)
For the easiest and fastest Pina Colada, add all the ingredients into the blender, except for the dark rum floater, and add 3-4 cups of ice. Blend it well until all smooth.
Divide the mixture among the glasses and carefully pour 1/2 oz. of dark rum on top.
Garnish with pineapple chunks, pineapple leaves, or maraschino cherries as you wish.
Pina Colada Version 2:
For absolutely best results, you will need to put in a little extra time but this version will have the strongest and brightest flavor.
First, blend frozen pineapple chunks, cream of coconut, and white rum together until all smooth.
Place the mixer pitcher into the freezer (if it's freezer-safe) or transfer the mixture into a freezer-safe container and freeze for 1-2 hours.
Then, blend it all together again and if you feel like you need to, add about a cup of ice. This will give you the strangest and most vibrant flavor. (But note that it will give you less servings because there will be less ice.)