Marcus Preston is a 4th grade boy at South Park Elementary. He makes his debut appearance in the Season Twenty-One episode, "Hummels & Heroin", where he personally investigates the sudden increase in deaths of entertainers dressed as popular cartoon characters. At his own 10th birthday party, he witnessed Chuck E. Cheese fatally overdose on opioid drugs while performing on stage. This traumatizing event led him to call a rally, and declare war on opioids.
Marcus is a short, chubby 4th Grader. He has curly black hair that is cut low on the sides, and high on the top. He dresses professionally and mature for his age. He can be seen sporting a green jacket, a brown v-neck sweater - with a horizontal, argyle print, and dark blue slacks. He also has a very distinct voice, speaking with force, but at a high pitch.
In the episode, "Hummels & Heroin", Marcus proves himself to be sentimental, astute, and ambitious. He took measures into his own hands to uncover the drug network responsible for the death of Chuck E. Cheese, and the other costumed characters. He persevered in his investigation, seeking to bring justice to all responsible parties. Using his impeccable investigative skills and logic, he followed-up on every promising lead - eventually leading him to the truth behind the untimely deaths of these beloved cartoon characters.
Though he appears quite abrasive and intimidating on the surface, He is also very sensitive. After all, his investigation was primarily fueled by his own admiration for Chuck E. and the other entertainers. He also burst into tears while speaking to Stan about his feelings about their deaths at the end of the episode. Despite his mature discourse and sophisticated analytical skills, Marcus is still a child (physically, psychologically, mentally, and emotionally). He genuinely believed that each of the costumed entertainers in fact were the actual cartoon characters that they represented.
- His original design had glasses.
- He is voiced by guest star Josh Gad - an American actor, fan of the series, and friend of Trey Parker and Matt Stone. He had previously been the original actor for Elder Arnold Cunningham in The Book of Mormon, which Parker and Stone co-wrote with Robert Lopez.
- "Hummels & Heroin" - Investigates further into the deaths of the party entertainers.