Blarggity Blarg-Tucker

Junior is an Alien, albeit a miniature one, created by Tucker via parasitic infection.

Season Four
Junior made no physical appearances in season four, but played an important role nonetheless. During Tucker, Caboose, Andy, The Alien, and Tex's trip on "The Great Journey", Tucker complains that The Alien is constantly standing over him while he sleeps. Tex writes it off as safeguarding of the sword, while Caboose concludes that the alien is either stealing the humans' sleeping technology to use against them or just stealing Tucker's breath.

Upon returning to Blood Gulch, Tucker begins throwing up and becoming moody, much to Blue Team and Andy's irritation. After a while, Church decides to call Doc/O'Malley to find out what's wrong. Upon investigating, Doc claims that Tucker is pregnant. This causes a lot of hysteria among Blue Team as Tucker claims it isn't his, Church claims it to be impossible, and Caboose is worried about it being contagious.

Tucker finally begins to give birth and while dealing with Red Team; Church finds out from Andy that aliens can impregnate humans with a parasitic embryo. Though Church still believes the pregnancy to be impossible. Junior finally appears at the end of season four (though only in voice) saying "Honk, honk, Blarg!" in a high pitch voice similar to Tucker's.

Season Five
In Episode 78 it again appeared in voice only while it was wrecking the base after Doc fed it half a gallon of Caboose's own blood, shouting high pitched Honks and Blarghs. Its first visual appearance was in Episode 80 as a mini version of an Elite with teal and blue armor. Church frequently tells himself that he will kill Junior, but never does anything aggressive to it. He also frequently talks about it being gross, despite it never having done anything remotely disgusting. Tucker only reacts to either of these tendencies once and quickly blames it on hormones when he does.

It appeared in Episode 91, while Doc was "examining" Sister. Tucker found it in Blue Base and it was a lot bigger than the last time it was seen. As Tucker tries to sneak a view of Sister without her armor on, Junior continues to blarg and honk, slightly irritating Tucker.

In Episode 94, Church, listening to a suggestion from Vic Jr., decides to launch an attack on Red Base. Church decides to send Junior, Doc, and Sister through the caves (again, per Vic Jr.'s suggestion), when Tucker decides to prepare Junior for the rest of his life. After giving Junior some "advice", Tucker finishes by telling Junior to "mix it up a little" with the girls. He then says Tex needs him and Church to back her up, following which Junior says "Blarg-Chicka-Honk-Honk," a twist on Tucker's infamous catch phrase. Tucker says its been handed down to Junior via "genetics".

In Episode 99, it was revealed to be the "Alien race savior", who the humans planned to have controlled by O'Malley to take control of the Aliens and win the war. After Tex beats up Tucker and takes his sword, she ushers the two aliens into the crashed pelican. After infecting herself with Omega, Tex takes the ship to complete Omega's plan, but Andy detonates and blows up the ship, "[scoring] two for Red Team."

Reconstruction
During Shiela's playback of her crash during of Reconstruction Chapter 5, Sheila notes that a hatch is opening, and Tex screams "Where are they going!?!" likely referring to Junior and the other alien, as no alien bodies were found near the crashed ship.

Recreation
It is revealed in Recreation Chapter 13 that Junior did survive, and is now with Tucker negotiating situations between Aliens and Humans, but makes no appearance in the series.

Simmons
Junior interaction with Simmons is next to none, but he does rip his spine out in the PSA "Let's All Go to the Movies" on Tucker's command.

Church
Despite Church's constant insulting of and threats to kill Junior (which he never follows through on), Junior remains mostly passive towards Church, doing nothing but blarging and honking in his presence.

Tucker
As father and son, Tucker and Junior (respectively) share a bond. Despite not knowing how to raise a kid at first, Tucker later found himself looking at minivans and generally "getting into the whole parenting thing." Junior seems to show happiness in being around and talking to Tucker, but was generally too young to show any real signs of family love. It should also be noted that after Junior's apparent death, Tucker simply walked away, saying "Yeah, fuck this!", though oddly, he became aggresive towards Wyoming when he revealed that his plans involved Junior, and in their last father-son meeting, Tucker bestowed 'words of wisdom' upon his son. He also hinted in a deleted scene that he didn't really believe Junior was dead, noting that "they don't treat death the same way we do".

Caboose
In return for a cookie and a glass of orange juice, Caboose willingly let Junior drink half a gallon of his blood. After being told to feed Junior again, Caboose timidly said "please no." In general despite Caboose's stated hate for babies(when emulating O'Malley's meanness), his relationship with Junior is mostly positive. He even expressed desire to scrapbook after Junior began growing up so fast.

Doc
Junior's first feeding, first words ("honk-honk", or purple), and first walk were all a direct result of Doc. Doc clearly was very fond of Junior, spending time with him a praising him happily. He even decided to send back Church's shower gift as punishment during Church's first attempt to kill Junior. Tucker even considered Doc his first choice as a babysitter.

Sister
Sister's first meeting of Junior was less than flattering for the little alien, she mistook him for a dog but quickly corrected herself by describing him as a "kid that looks like a dog". During her trip through the caves, she was slightly supportive of Junior, calling him cheerily calling attention to him as he fell behind. A deleted scene shows Sister babysitting Junior, where the relationship was shown to be much less positive, as she constantly screamed at him and locked him in the closet and complained about having to feed him.

Production
The Alien baby was created using an unusual technique called forced perspective. According to series creators in the extras of the season 5 DVD set, the Alien baby was filmed by having the Covenant player stand further away, while aiming the camera in such a way as to obscure the feet or pull focus away from ground. This causes the illusion that the alien and other characters (typically Tucker) were standing closer than they were, eliminating depth perception. While this technique worked most of the time, some shots were impossible without some digital editing.

Trivia

 * Junior is mentioned by Tucker as being an ambassador like he is in Chapter 13 of Recreation which proves that Junior survived the Pelican blowing up.