Pheromone

The Pheromones are a plot-specific item in BioShock. They are used on Big Daddies in order to attract the Little Sisters. The scent of the pheromones is disagreeable to the human sense of smell, but the Little Sisters find it attractive for reasons unknown. Four samples of pheromones can be found in the Little Wonders Educational Facility, but Jack needs only acquire three to become a Big Daddy.