The Alien Prisoner is an abnormally muscular fugitive imprisoned in the Alien Ship by his people due to his unstable nature and violent intentions. He is unintentionally released by the player when they destroy a particular power generator, shutting off the laser bars containing him in his cell. In the short cutscene, he is seen lifting weights while sitting on a toilet, but when he sees that the bars have been disabled, he frantically seizes his chance to escape, while claiming revenge by dooming his captor's ship at the same time. He drops the dumbbell, runs to the control panel, sits down, and starts to bang on it rapidly. This ejects him from the ship, while also setting a self-destruct sequence with a one-minute countdown, in which the player must escape while avoiding obstacles and Aliens. The ship explodes just as the player escapes.
He has a mild yellow skin tone and very muscular build. He has four fingers and three toes. He has black Beady eyes along with an unsettled mouth. Unlike the other aliens, he is barefoot. The Alien Prisoner wears a white tank top paired with black shorts.
- He was originally from the game Alien Hominid.
- Because the Alien Prisoner escapes during Medieval times, it makes perfect sense that he appears as a boss that must be fought in the The Behemoth™ game Alien Hominid, which takes place in modern times, long after the escape.
- His right antenna has a small bend in it.
- The Alien Prisoner is not in fact a Beefy Alien, although he has a beefy body structure.