Slim is very nervous and erratic, and is usually reprimanded by P.T. Flea. Apparently, he is unhappy with his position at the circus troupe, as his boss constantly casts him as a prop instead of an actual character. He is best friends with Heimlich and Francis, and seems to be tolerant of Francis' aggressive nature.
Slim is a cinnamon brown stick insect and a clown in P.T. Flea's circus troupe. It appears that he is unhappy with his position at the circus troupe, as his boss constantly casts him as a prop instead of a character, with such castings as a broom, a pole, a stick and a splinter. He is shown to be best friends with Heimlich and Francis, and often treats other bugs with more respect in contrast to Francis' aggressive nature. However, he seems to tolerate it, as seen when he calmly broke up a fight between Francis and a couple of flies during a performance.
Unlike most stick insects, Slim does not have wings and cannot fly. Because of this, Francis usually carries him for transport. During the Fake bird attack by Flik he pretends to be injured by it, frightening Hopper and he sees P.T Flea about to set fire on the fake bird realizing he's going to help Hopper and tries to stop him. At one point, Francis, while chasing after Hopper who kidnapped Flik in retribution for the ant rebellion, accidentally loses Slim in a branch group and he was later found. At the end of the film, when the circus bugs leave Ant Island, Slim rides on the back of the circus wagon since Francis helps Manny carry Heimlich.
- In an outtake, Slim is being carried by Francis and he accidentally swallows a bug. In another outtake, when trying to scare Hopper, Slim ends up getting berry juice in his eye, causing him to cry out in pain. As Hopper laughs at him, he demands that the crew stop the camera.
- Slim's voice actor David Hyde Pierce also provides the voice of Dr. Delbert Doppler in Treasure Planet.
- Slim appears in the end credits of Cars as a brown car with big mirrors.
- Slim's line, "How low can you go?" is later used by one of the Barbie dolls in the next film, Toy Story 2.
- His name is a reference to an evil clown from Killer Klowns from Outer Space.