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.