Alien X is the Cosmitrix's DNA sample of a Celestialsapien from the Forge of Creation in Ben 10: Cosmicverse
Alien X is a humanoid alien whose entire body is solid black, excluding his hands, which are white. He has tiny white star-like spots all over his body, giving him the appearance of a starry night sky. His eyes are green and lack pupils, and his forehead bears three horn-like protrusions.
Alien X has three personalities: Serena, the "voice of love and compassion", Bellicus, the "voice of rage and aggression", and Ben, the "voice of reason". All three of these voices combine to form Alien X's speech. Otherwise, Alien X is silent. The only things he will say are what he will be doing - what Ben, Bellicus, and Serena have agreed to do.
As Serena and Bellicus have been arguing for eternity and before they had no tiebreaker, getting them to focus on any present task is difficult at best. This leaves Alien X's body trapped in place, floating about a foot above the ground until an agreement is made.
Powers and Abilities
Alien X is omnipotent, being able to warp reality, time, and space with ease and at any level he wishes. Even his thoughts can become real. In short, Alien X can do anything.
Alien X can create time waves to reverse events.
Alien X can create and recreate an entire universe at will.
Alien X is nearly invulnerable, as he was completely unharmed when the Annihilargh destroyed the universe around him.
Alien X can self-duplicate, create galaxies to suck in other beings, and travel at high speeds. He also possesses superhuman strength and the ability to grow to a gigantic size. He is skilled at hand-to-hand combat.
Alien X possesses telekinesis and is capable of deflecting energy attacks, such as those generated by a Prypiatosian-B.
Alien X possesses X-ray vision, meaning he can see through objects such as a mountain. He can also regenerate his limbs should they be severed.
Alien X can survive a timeline destruction.
Simply he is like a god.
In order for Alien X to perform any action, including simple movement and transforming back, all three of his personalities must agree to do so. This has proven to be a major weakness, as Serena and Bellicus were not interested in dealing with present affairs and wanted to finish past ones that were not possible to deal with without Ben. In Omniverse, Ben still needs to consult Bellicus and Serena to get control. He is just better at it now.
Alien X is vulnerable to having his powers absorbed, as Ben and Azmuth have implied that Darkstar and Osmosians, respectively, can absorb his omnipotent powers.
Alien X's actions onto reality can be neutralized and reversed by the intervention of other Celestialsapiens.
Alien X can be devoured by a Gourmand, who would either digest him or spit him back out.
Alien X can be affected by a Nemuina's sleeping dust.
Alien X's personalities can be scared by Toepick's species' faces.
Alien X's life force can be drained by a Vladat. He also cannot survive on Anur Vladias.
Alien X's powers may be limited to the basic cosmic laws of other universes or may not work depending on the universe.
Alien X cannot manipulate mana directly; he would have to alter the universe to change the nature of mana first. Also, his cosmic powers do not work well against magic.
Alien X is so powerful that he doesn't need any Ultimate or Cosmic form.