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 sky. His eyes are green and pupiless, and his forehead bears three horns.
In John Smith 10, he has his UAF appearance until Omniverse, where he gains his Omniverse appearance.
In Jane Smith 10, she has the appearance of the Celestialsapien mother shown in the Forge of Creation, having an hourglass shape and a curved chest. She is regular height, however.
Alien X is unlocked when the Omnitrix resets after defeating the Highbreed. While considered to be his most powerful form, he is used scarcely. The personalities, Bellicus and Serena, usually combat his choices, mainly Bellicus, but they do recognize when they need to act over when they don't have to.
Alien X is renamed Alien Y, and is the last revealed alien of her original 10. Bellicus is more extremist towards fighting, while Serena is more extremist towards love and compassion. When used by Janezarro, she has full control, due to her undead state and lack of her own efficient thought process and decision making decisions.
