Mortimer "Morty" Smith Jr. is Morty Smith's son. He was conceived by Morty and a Gazorpian sex robot named Gwendolyn in the episode "Raising Gazorpazorp." Morty Jr. grew from an infant to a full adult at a hyper-increased rate, allowing him to quickly outgrow his father.
Being half-Gazorpian, Morty Jr. is prone to violence and destruction and has a difficult time fending off these urges. While he has the humanistic tendencies to listen and be non-violent, his Gazorpian genetics influence him to seek out destruction and death. After being swayed with words, he decides to be a creative type and later channels his destructive nature in writing.
Post-credits, an aged Morty Jr. has an interview about a book he wrote, "My Horrible Father". Becoming much calmer and suppressing his Gazorpian urges to kill and conquer, Morty Jr. expresses a cynic and dark view of his childhood, criticizing his father Morty for raising him imprisoned, even though he knew of his own violent and sadistic senses and would have most likely killed many innocent people.
Despite having a human father, Morty Jr. possesses the traits and abilities common among full-Gazorpian males, including claws, fangs, superhuman strength, destructive impulses, crimson skin, arms in place of ears, and a short lifespan. Unlike full-Gazorpian males, who possess four eyes, tufts of light blue fur and bestial faces when fully-grown, Morty Jr. has two eyes, no fur, and a mostly humanoid face well into adulthood.
- Aging quickly, Morty Jr., like most citizens of Gazorpazorp, grew from an infant to a young adult in less than 24 hours.
- Unlike other citizens of Gazorpazorp, Morty Jr. possesses 2 main arms instead of 4. This trait was likely passed down from Morty's genes.
- His favorite channel is the History Channel.
- Unlike his father, Morty Jr. hates cartoons and video games.
- Before his father told him, Morty Jr. was unaware that he was an alien-human hybrid as he asked, "I am an alien?"
- He can be seen on the Loot Crate exclusive puzzle.