Alien X is the Omnitrix's DNA sample of a Celestialsapien from the Forge of Creation.
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.
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 wears the Omnitrix symbol on his chest.
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. He is also nearly invulnerable, as he was completely unharmed when the Anihilaarg destroyed the universe around him.
Alien X can self-duplicate and create galaxies to suck in other beings. He is also capable of high speed travel, superhuman strength, and the ability to grow to a gigantic size. He appears to be skilled at hand-to-hand combat.
Alien X possesses telekinesis and is capable of deflecting energy attacks.
Alien X can destroy a multiverse, but it would take six thoughts.
Alien X can bond his power with other Celestialsapiens if they agreed.
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 weren't interested in dealing with present affairs and wanted to finish past ones that weren't possible to deal with without Ben.
This weakness was referenced by Professor Paradox, when he revealed that there is an alternate timeline where Albedo transformed into Negative Alien X and was stuck motionless for nearly a year.
Ben still needs to consult Bellicus and Serena to get control, he's just better at it now.
Alien X is vulnerable to having his powers absorbed, as Ben and Azmuth have implied that Darkstar and Osmosians can absorb his omnipotent powers. This was in fact Aggregor's master plan - he collected the powers of 5 aliens (Galapagus, Bivalvan, Andreas, Ra'ad, P'andor) from the Andromeda galaxy to gain access to the Map of Infinity, in order to gain access to the Forge of Creation so he could absorb the powers of a newborn Celestialsapien.
- Ben acknowledges Alien X as his most powerful alien, but concedes that transforming into him is not worth the cost.
- In Alien Force, Ben served as the tie breaker for Alien X; if two of the personalities agreed on something, the motion was carried. This was altered in Omniverse, as all three personalities must agree.
- In Universe vs. Tennyson, Ben offers to let the two personalities argue between themselves for eternity if they give him full control over Alien X. Serena agrees, followed by an initially reluctant Bellicus, giving Ben full control over Alien X.
- Alien X's starred body isn't simply "aesthetic"; rather, Alien X, and by extension all Celestialsapiens contain their own "pocket universes". This explains how Paradox was able to travel inside Alien X and speak to Ben whilst he was arguing with Serena and Bellicus before reversing the transformation.
- Sometime between the events of The Final Battle: Part 2 and The Forge of Creation, Ben had had the Ultimatrix modified to lock the Alien X transformation, to both prevent himself from accidentally transforming into him and as a safety measure to keep someone like Albedo from using it. The only way to access Alien X was to use a pair of keys in Gwen and Kevin's possession.
- In A Jolt from the Past, Rook speaks of Alien X, but believes he is just a rumor. Ben tries to convince him that Alien X is real, but Rook doesn't believe him and asks Ben to transform and show him, which Ben refused. This conversation happens again in So Long, and Thanks for All the Smoothies, and by the end of the episode, Rook sees Alien X for real. But after the universe is restored by Ben, his memory of Alien X no longer remains and he disbelieves Ben when the latter says that he used Alien X to recreate the Universe. Finally, on seeing Celestialsapiens and Alien X in Universe vs. Tennyson, Rook believes Ben.
- In Andreas' Fault, a fan of Ben refers to the Alien X smoothie as a disappointment as well as saying it tastes like "filler." This is a reference to Alien X's constant standing in the series.
- Ironically, in many promotional images of him, Alien X is posing dramatically (like in the openings to Alien Force and Ultimate Alien), while in the actual series, most of the time, he is frozen in a standing-up position.
- Alien X was the first alien featured in Alien Force and Ultimate Alien to not be voiced by Dee Bradley Baker.
- Before Alien X appeared, the opening of Alien Force showed only a silhouette of him. After he appeared, it began showing his full image.
- Alien X is a Nano and a former NPC in the game FusionFall.
- In Project Exonaut, Alien X is a level 10 suit.
- Alien X with his celestial abilities and appearance are similar to the hero Captain Universe from Marvel Comics.
- Alien X was featured in Death Battle in Ben 10 Vs Green Lantern on May 22nd, 2019.