|Residence||Area 51, Earth (formerly)|
|Age||at least 50|
|Occupation(s)|| Prisoner (formerly)|
|Powers and Abilities|
Retractible Tail Stinger
|Relatives|| Unnamed mate (deceased)|
Unnamed children (deceased)
|Alias|| Missing Alien Prisoner (Rath)|
Prisoner Chameleon (Gwen)
|Voice Actor||Dee Bradley Baker|
|First Appearance||Prisoner Number 775 Is Missing|
Prisoner 775 is the main villain and titular character in the episode Prisoner Number 775 Is Missing.
Prisoner 775 was part of a revolution on his home planet that was lost. His mate and children died and he thought there was nothing left to live for. He was exiled from his homeworld by an oppressive dictator and crashed on Earth where he ended up imprisoned in the secret Area 51, held on suspicion of being a terrorist.
Ultimate AlienAfter Area 51 is visited by Old George, Prisoner 775 escapes. He wanted to kill Colonel Rozum and his family for his association with the US Air Force for imprisoning him for years and letting his family die (although Kevin Levin suggested him to "even the score" with Ben advising him to "seek justice"). However, he was stopped by Ben as Ultimate Wildmutt. He begged to be executed, to rejoin with his family, but to no avial. Prisoner 775 was handed over to the Plumbers for interrogation as his DNA is scanned by Ben's Ultimatrix to unlock ChamAlien.
Ben 10: Ultimate Alien
- Prisoner Number 775 Is Missing (first appearance)
- When Prisoner 775 turns invisible, the way his mouth and eyes are clear for a while as the rest of him disappears is similar to the Cheshire Cat in Alice in Wonderland.
- Both Prisoner 775 and ChamAlien bear a strong physical resemblance to Disney Pixar's Monsters Inc. character, Randall Boggs, all three being reptilian, based on chameleons, and being able to blend in with their surroundings.