Rogue Xenomorph

In the comic Aliens: Rogue, a mad scientist engineered the Rogue Alien: a male Xenomorph designed as a weapon to rival the queen caste and thus help rid the Earth of its alien infestation (see Earth Hive, Nightmare Asylum, Female War, and Genocide). However, the Rogue escapes and wreaks havoc until it is torn apart by a Queen.

In the book of the same name, the Rogue, while believed to be more powerful than the Queen, the scientist is shocked to find the Queen is in fact the superior specimen. While the Rogue is larger and stronger, the Queen's superior speed and intellect enable her to easily dodge the Rogue's brutish attacks while she slowly wears it down and finally slaughters it. The scientist, Ernst Kleist, is subsequently killed when he uses a sound cannon on the Queen until it goes critical, destroying the asteroid base he is on. The Rogue is seemingly much more aggressive and mercilessly attacks the smaller castes of Aliens. This is Illustrated when Professor Kleist finds the crushed corpses of the elite Praetorian guard of the queen. Interestingly, the Rogue appears to have been engineered to ignore humans - when exposed to a human prisoner, the Rogue examined him closely at first, but did not attack and finally ignored him completely. This may be due to a rogue caste not having as strong a sense to use humans to breed as a queen caste. Or maybe its simply because the human prisoner was un-armed and restrained so posed no threat. The Rogue's recklessness is also shown when it destroys the barrier that separates the Alien sector and the Human sector, allowing alien drones to pour into the human sector.