|Type|| Crusher = Giant Chaser
Soldier = Chaser
Spitter = Ranged Chaser
|Signs of nearing||Roaring, Shrieking, and Breathing|
|Theme song||Epic Battle Theme/Predator vs. Predalien|
|Partners||Xenomorph Soldier duplicates, Xenomorph Spitter duplicates & Xenomorph Crusher|
|Stunnable?|| Crusher = No
Soldier = Yes
Spitter = Yes
The Xenomorph X121, better known just as Xenomorph (which literally translates to "unknown shape") or the Alien, are a group of bosses that appeared on Slender Fortress.
The Xenomorphs are a race of hostile extraterrestrials from the Alien franchise. While they prey upon humans like predators with their unmatchable speed, strength, and durability, their society is based off a caste system like a bee hive or ant's nest.
In Slender FortressEdit
Xenomorphs are bosses in boss pack 3. Xenomorphs are a group of alien bosses that work together to kill their victims. Only the two weaker ones can be stunned.