Thirdspace Alien

"They are a power beyond comprehension. A hunger beyond understanding. They are anti-life itself, older even than we were. Telepathic, all of them, they modified the gate so that it enhances their telepathic impulses, created an army of our own people willing to die for them."

- The Vorlons, speaking through Lyta Alexander

The Thirdspace Aliens are the unnamed dominant species native to the third known spatial realm, beyond both normal space and hyperspace. They believe themselves superior to all other lifeforms, and aim to destroy all life that is not their own.

An extremely ancient and highly hostile species, these non-humanoid telepaths have exterminated thousands of species from their native dimension and will not think twice about doing the same on the other realms if they have the opportunity. Fortunately, a gate must be opened on both realms to allow their passage.

Biology
They physically resembles a massive crustacean, with three pairs of red eyes or eye-like structures; a hidden mouth filled with teeth; articulated legs; a retractable tail and a number of retractable grasping tentacles. They are seemingly able to fly despite the lack of visible flying organs, and also turn wholly or partially invisible. Most notably, they have the ability to telepathically influence the minds of other beings of any species; humanoids and Vorlons alike; and use it to turn large sections of their enemies' population aggressive towards each other. They can also broadcast dreams into the minds of others.

Technology
To back up their aggressive expansionism and xenophobia, the Thirdspace dwellers possess technology beyond the level of even the ancient species from normal space. Their ships appear organic-looking and protected by a powerful energy shield, and their plasma weapons can easily disable or destroy an enemy vessel. The city of the Thirdspace creatures has a bizarre architecture, with hundreds of short buildings surrounding a massive twisted tree-like tower orbited by additional floating structures.

Appearances

 * Babylon 5: Thirdspace (1998)

Behind the scenes
The Thirdspace alien creatures, as well as their city and artifact were all designed by Wayne Barlowe of Expedition fame; taking inspiration from the Lovecraft mythos.

In one of the Babylon 5 RPG supplements, it is said that the Thirdspace Aliens were a race of beings equivalent to the First Ones in our universe, perhaps their universe's equivalent to the First Born or Vorlons, but unlike those races instead of guiding and nurturing lesser species they exterminated them. It is also said that the Hand are their emissaries, similar to the Drahk's relationship with the Shadows.