The Drone, also commonly referred to as the Warrior, Soldier, Worker or Lurker, and designated a "Stage 3" Xenomorph by Weyland-Yutani scientists, is the most common adult form of the species Xenomorph XX121. Between 7–8 feet in height and 14–16 feet long (including their tail), Drones are by far the most widespread caste of Xenomorph, acting as the species' principal offensive unit in combat situations. Among the roles carried out by Drones are the construction of Hives, the elimination of threats and the capture of potential hosts for reproduction. As with many forms of the Xenomorph, the exact physical characteristics of the Drone can vary; most obviously, the exact makeup of the creature's head carapace has been seen to differ between individuals, with both smooth and ridged examples observed. Other minor differences have also been noted. Drones are fast and reasonably tough, and equally capable of carrying out premeditated stealth attacks as well as engaging in savage close-quarters combat. Even in death the Drone is dangerous, as its pressurized bloodstream will often cause it to burst apart if sufficiently damaged, drenching nearby enemies in acid blood. They are also capable of spitting cysts of this acid at their enemies. One particular Drone from Acheron was responsible for infiltrating the USCSS Nostromo and killing virtually all of its crew. The creature was ultimately ejected into space and incinerated in the engines of the shuttle Narcissus by Ellen Ripley.