Junior

Junior is one of Big Chill's Offspring appearing in Ben 10: Ultimate Omniverse. Credit goes to Startreknerd11011011 for making this idea.

Species
Necrofriggian/human/numerous other species

Backstory
One of Big Chill's babies, he and his sibblings originally travelled to the Kylmyys' Sun, like most other Necrofriggian offspring, in order to feed off of the solar energy until they matured. However, Junior was born... different... unlike his siblings, his Egg received a burst of energy from the Omnitrix, mutating it. Junior decided to return to his "Mama" and traveled back to earth, he grew rather fast and by the time he was 2, he already had the maturity of a 10 year old.

He found Ben and decided to follow him around, calling him Mama (Something which Kevin and Gwen have agreed to never... EVER... let Ben live down.) However, Ben told Junior that he couldn't look after him, he and Julie  attempted to look after Junior like his parents, with humorous consequences, however they decided that they just weren't ready to be parents yet. Junior overheard them talking and ran away, but was captured shortly after by Doctor Animo, who wanted to study him.

Animo quickly learned he had made a mistake when Junior transformed and defeated a mutated Lion/Wolf he had created, but Junior was quickly outnumbered by the rest of the Lion/Wolf pack. Junior proceeded to go Ultimate, just as Ben, Rook and Julie arrived (Julie smashing a tennis-racket over a Lion/Wolf's head yelling "GET AWAY FROM MY BABY!!!" in a fit of passion.) it was then that Animo released his "Latest, Greatest creation!" a giant Lion/Bear/Wolf, Ben and Rook attempted to fight it, Ben becoming Big Chill, but they were defeated, it was then that Junior got mad and transformed to look like a hybrid of Big Chill and Humongousaur. Ben and Rook were both extremely confused by this (Rook stating that he had no idea that Necrofriggians were capable of such a thing. But Julie quickly figuring out that it must have been something to do with him being born from the Omnitrix.)

Junior proceeded to defeat Doctor Animo and returned to Ben and Julie, promising to be good. But Julie stating, that though she does care for him, she isn't ready to be a mother just yet. It was then that Ben gets a call from Azmuth on his Omnitrix. Azmuth explains that he had been tracking Junior ever since he was born, curious as to the effect of the Omnitrix on new born creatures, he found out that Junior's DNA is tied directly into the Codon Stream, meaning Juniors bio-chemestry is effected by it. When Ben went Ultimate with Big Chill for the first time, it effected the Codon Steam, feeding new DNA into it, allowing Junior was able to access that DNA as well. It is also what allows him to half transform into other aliens. Azmuth suggests sending Junior to him for further testing, but Junior says he wants to stay on earth with his Mama, as he clutches Ben's Leg ("Not a word..." Ben says to Rook, Rook fighting back a smile)

Azmuth then suggests sending the boy to live with someone on earth that can, not only teach him discipline (Like his Mama, something he lacks.) but can also look after him as a member of the family. Ben says he knows just the people. He sends Junior to live with Ester and the Kraaho in Under-City. He still joins Ben on missions, and though he has gained a lot of discipline from living with the Kraaho, he still calls Ben Mama, mainly to embarrass him though.

Skills
Can "Go Ultimate" at will, can transform his body to look either Human or Necrofriggian at will. Can transform his body to look like a hybrid of a Necrofriggian and several different aliens (Anything in the Codon Stream)

Ben 10: Ultimate Omniverse
In Ben 10: Ultimate Omniverse he is 2.