Carl is a light green fish with mustard-yellow fins and pale green lips. He is usually cross-eyed and smiling. He wears big, nerdy, light blue glasses, a tight lavender shirt with a purple and pink tie, tight brown pants with a dark brown belt, and black and white shoes. He also has a name tag on his shirt.
Carl becomes the new manager of Krabby O'Monday's shortly after Mr. Krabs retires. He quickly gives Squidward and SpongeBob their new uniforms and employee manuals, and then tells them to be at work first thing tomorrow.
Later, Squidward is upsetting a child with a lousy Krabby O'Monday's birthday song. Because of this, Carl confronts him and tells him to have sincere service with a smile, or he will be turned over to Human Resources. This causes Squidward to act happy and work faster.
Later, Mr. Krabs returns to Krabby O'Monday's because he is bored of retirement. He goes to clean a table, which Squidward kindly asks him to do. Mr. Krabs asks Squidward why he is so happy, and Squidward whispers "They're watching us." Mr. Krabs gets confused and says Carl is a "real pain in the hindquarters," causing him to get angry. Squidward, afraid to get caught by Carl, tries to show Mr. Krabs a message he wrote that reads "Help me!" in his employee handbook. Mr. Krabs reads it out loud, just when Carl shows up. Carl asks what they are doing and Squidward lies and says he is showing Mr. Krabs article 24, section 3 of his employee handbook to Eugene.
Carl believes him and tells him to "Cut the chatter, pick up a platter. Good job, Squidward." Squidward runs off. Mr. Krabs, confused, asks Carl what he has done to Squidward. Carl slowly backs up into Human Resources and says "The less you know Eugene, the better."
Later, Mr. Krabs discovers that Krabby O'Monday's was using synthetic Krabby Patties. He clogs the machine and starts scaring the customers away with the synthetic patties. This causes Carl to get angry and tells him he is in violation with his contract. This makes Mr. Krabs angrier, and he starts destroying the Krabby O'Monday's.
Carl then calls up Howard Blandy and tells him "Code red, free thinker." Blandy arrives shortly, but soon, the clogged synthetic machine explodes, causing Carl to be swept away by the synthetic sludge. He then asks if he will still get a raise while being swept away.
"Mall Girl Pearl"
Carl is among the many episodic characters who reappear as a cameo in the Bikini Bottom Mall.