Carlos

Carlos is one of the main characters of the Horror Magic School Bus. He is one of Ms. Frizzle's favorites, being chosen for his humor sometime in the 80s. He is one of Stephen's friends and homeroom classmates, introduced in Episode 11 when he warns Stephen to ask less questions so that he can go unnoticed in Ms. Frizzle's class. He is 12 years old, but has spent about 34 years trapped in the time loop.

Personality
Carlos is very cynical and has a dry sense of humor. Like in the original show, he has a love of puns. He has been in Ms. Frizzle's class for a long time, which has lead to him developing a nihilistic point of view. Because of this, he no longer cares about other people and tends to be rude, abrasive and self-centered. He is also shown to be somewhat cruel, playing pranks on or tricking other students, especially Ralphie, which generally ends in their death. He's particularly lazy, as he hates worksheets and prefers to copy Stephen's answers instead of filling them out.

Physical Description
Carlos is played by the creator of the show, Cleric. He is always shown in a loose-fitting dark blue sweater with sleeves rolled up to his elbows over a T-shirt. This outfit is confirmed to represent him in a video displaying the outfits of the characters.

Stephen
Despite Carlos generally not caring about others, he has grown to like Stephen and has become friends with him, often trying to help him by giving him advice and explaining things to him. However, he still likes to mess with Stephen and sometimes doesn't answer his questions out of annoyance or apathy.

Keesha
In the beginning of the series, Carlos and Keesha do not like each other and their first interaction on camera is shown to be cold. According to the creator, Carlos thinks Keesha is a bitch. Later on in the series, he appears to warm up to her as he decides to join a team to investigate Ms. Frizzle with her and Stephen.

Troy
Carlos shows interest in Troy and tries to stop him from being put in detention, but finds Troy's constant fear of Ms. Frizzle's field trips to be annoying.

Ms. Frizzle
Carlos is cautious of Ms. Frizzle and somewhat afraid of her, but is somewhat defiant and at times treats her with irreverence.

Unnamed Student
In line with his cynical and self-centered nature, Carlos displays a distaste for the unnamed student due to the student's apparent naivete. As such, he convinces the student to approach Ms. Frizzle and be put in detention.

Ralphie
Carlos seems to dislike Ralphie because of his stupidity and mostly see him as a test subject, using him for lethal experiments and entertaining himself by tricking Ralphie into dying or encouraging Ralphie to do deadly activities.

Dorothy Ann
Carlos appears to be amused by Dorothy Ann, not taking her hero worship of Ms. Frizzle seriously and seeking to entertain himself with her rivalry with Stephen.

Fruit Snacks
Carlos has developed a substantial love of fruit snacks over his time in the time loop, holding them in higher regard than many of his classmates. He eats them for every meal, and has even tried to rob Troy of his fruit snacks while he was unconscious.