Slither is an optional Boss that must be killed to complete Altar Ego: Godless Monsters. It is a Scythid, blue in colour with a pair of enormous mandibles, worshipped by a group of Bandits in the Rust Commons. He can be found in the farthest north location of The Rust Commons East.
Slither moves very fast but attacks just like a regular Scythid Crawler, even with the telegraphing pause before it attacks. It also shares the Scythid vulnerability to all forms of non-elemental damage, including damage delivered by regular melee attacks. So just keep strafing to the side and wait for it to lunge at empty air, then whip around and unload a few blasts with a good Shotgun at point-blank range, or spank it to death with melee attacks or just lure it outside of the anti-outrunner barrier and run it over for an instant kill.
The first time that Slither is fought for the mission, there are no other Scythids. When returning for playthrough 2.5, there are many of them. This makes the Soldier's turret much less useful regardless of upgrades, since, due to the number of enemies, it is unlikely to actually attack Slither itself. Slither is able to hide among the grass and other rubble, so it's best to use an Incendiary or Corrosive weapon, just to make him easier to locate should his small size become an issue.
- After Playthrough 2, Slither will sometimes drop The Dove, which is the quest reward for Altar Ego: Godless Monsters.
- Slither has also been known to drop Eridian weapons on rare occasions.
- The name Slither is likely a reference to the movie "Slither" under the genre of Horror 18+, from the book of John Halkin.
- The fact that Slither is a Scythid Crawler is likely a joke, as the player may have thought they would fight something bigger and stronger.