Trixie has the typical dark colors a Xenomorph does, and its smooth dome could be indicative of a Drone or Warrior caste. It has been outfitted with a special metallic harness by the scientists supervising it.
BiographyTrixie was presumably born in captivity and subjected to tests involving Telepathine, a substance that could allow non-xenomorphs to influence Xenomorph behavior. Mostly a background character, Trixie comes to forefront as Church's weapon of choice when he chooses to dispose of Crespi and McGuinness, trapping them in the maze it resides in. The creature manages to badly damage Crespi, who'd already been wounded by a volt of electricity by Church. It Headbites him through the back, which cripples him. Not wanting to die at the hands of the alien, McGuiness snaps his neck, then continues on after Church in a rage, Trixie not far behind.
Trixie is about to kill McGuinness, but Church shocks him, wanting to make the conflict last. McGuinness screams at the alien in frustrations when it goes to grab her again and it backs down, hinting at some Telepathine, natural or articifial, in her blood. McGuinness is able to jump the railing, bash Church's head into it, and throw him down to the Alien waiting below. It prepares to Headbite him, but apparently never succeeds as Church is seen more or less fine in a hospital bed as the comic ends.
Trixie's fate is unknown.