Jasper was a 6th grader student who was turned into a "Mutant Sixth Grader" by Dr. Mephesto. For now he only appeared in South Park: The Fractured But Whole, as an enemy that appears in the quest "The Many Asses of Dr. Mephesto".
In one part of the game, The New Kid will find five 6th graders camping in an abandoned place next to the school. They were talking about Jasper disappearing for three days, one of them suggests telling his parents but another immediately replies that they shouldn't because they think their parents are dumb and says Jasper probably found some porn tape.
Jasper could be only seen in his mutated version. He has black hair and wears a dark blue cap, a red hood and pale green pants. He has a gorilla-like body, and like almost every mutation created by Dr. Mephesto, he has several asses in his body. It is unknown what Jasper was like before he became a mutant.