Big Sisters are formidable beings that are known for their agility and Plasmid powers. They wield large, wrist-mounted needles on their left arms, which are used primarily for melee attacks and extracting ADAM in a manner similar to a Little Sister’s extracting needle and allows the Big Sister to regenerate health in combat from Splicers. Big Sisters are the only creatures in Rapture shown to be able to damage the exterior glass windows of the city, something that shooting bullets, grenades, a drill or any other weapon have failed to do. The Big Sisters were meant to accommodate, protect, and transport Little Sisters, and they have a cage-like basket on their backs for such purposes. The Little Sisters appear to frequently travel with the Big Sisters, and they have taken to decorating their refuges by adorning their cage-baskets with ribbons, and scrawling childish doodles on the Big Sisters’ oxygen tanks.