8 ice cubes, divided
4 fluid ounces passion fruit-flavored syrup
2 fluid ounces pineapple juice
1 fluid ounce fresh lime juice
1 fluid ounce dark rum
1 fluid ounce light rum
Place 2 ice cubes in a cocktail shaker; add passion fruit-flavored syrup, pineapple juice, lime juice, dark rum, and light rum. Cover shaker and shake.
Fill a 14-ounce glass with remaining ice and strain drink over ice.