Chelsea is in the 4th grade and is one of Clarence’s classmates, making her about 9 years old. Chelsea is the second-highest scoring student in the class (behind Breehn). She could be considered a "tomboy" and tries to join Clarence, Jeff and Sumo's guy's club. Taller than most of her classmates (With an exception for Amy, Nathan, and Try, who are among the most tallest), with an obsession with creepy stuff, Chelsea gives Sumo a run for his money when the two "battle" to see who can gross the other out first (Too Gross For Comfort). The battle ends in a humorous tie when Chelsea and Sumo both think of the same gross thing to do - kiss. The two open their eyes and, in disgust, run away from each other. Chelsea is best friends with Alison. Armed with a morbid sense of humor and blunt honesty, Chelsea is the kind of girl to speak her mind. Her teasing scares Clarence and Jeff but is a soothing balm for Sumo. Chelsea loves creepy and weird things.
Chelsea has brown skin and a ginormous bush of dense brown hair. She also has buck teeth with braces, though her front two teeth are fake. She wears a purple turtle neck, a light green skirt (or possibly undershirt), pastel green leggings and Mary Jane style dark green shoes.
She and Kimby were like this in Plant Daddies, to where Kimby didn't know much with Chelsea as they both are assigned as a work duo, their relationship started off as they trying to set a difference of they normally do, but once both got to set it with each other, they began to get along.
She and Alison were best friends as seen in Clarence's Millions, but however recently she hasn't been seen with Alison in a while.