Xenomorph

Description
The Xenomorph, is the main type of alien in the Apocalypse universe. It appears to have no eyes therefore it is determined that they sense the area surrounding them with their spine-like tail. For the most part, the Xenomorph is an easy opponent on the battlefield for The Hunters, though a survivor could easily be killed if attack by one. As a Xenomorph has tough scaly skin, it is able to deflect many attacks dealt by regular survivors.

Ways To Kill A Xenomorph
The main method to kill a Xenomorph is to first, cut off it's tail (this is mainly done by The Hunters with a sharp blade, mainly a katana, though in some cases this can be done with 'The Ultimate Rainbow Sword') and then ,while it's tail is not regenerated and it has lost all sense of tracking your location, to decapitate it.