Slith

The Slith are aliens that appear in Unreal and Return to Na Pali, and in de Invasion gametype of Unreal Tournament 2004. There is almost no background story for these creatures.

Slith are the Skaarj's amphibian cousins, and they fight alongside them on Na Pali, most commonly throughout the temple of Chizra. They are green, serpent-like creatures that can slither around on land and swim very fast under water. They can spit acidic saliva or use their claws to attack their enemies.

Slith are immune to the GES from the Bio Rifle. Since the Skaarj are immune to the Bio Rifle's "Bio Mist Cloud" in UC2 it seems the genetic makeup somehow makes the genus less susceptible to the GES's negative effects.