Combine the drink mix with 4 ounces cold water in a glass. Stir to dissolve.
Transfer to a blender.
Add the rum, lime juice, strawberries, and ice to the blender, and blend at high speed until slushy and uniform.
Pour into a glass and add a straw. Garnish with strawberries and top with whipped topping, if using. Slurp that baby up!