They were both voiced by the late Dan Gerson.
Needleman is very skinny, has light brown skin, a short tail, a large red nose, and two upward-pointing horns on either side of his head. Smitty has light green skin and four arms, and resembles a slug. While wearing his hat, Smitty has his orange fin-like hair over one of his eyes, a hairstyle known as an emo.
They work on the scare floor as general maintenance and errand monsters at Monsters, Inc. They're silly teenaged employees of the company. Needleman sometimes scolds Smitty for saying something he doesn't like or is just being stupid.
Needleman, a thin brownish monster, and Smitty, his short greenish friend, worship the ground that Sulley walks on. They really support Sulley in his race to beat the all time scare record and have a lot of respect for all the scarers on the floor. They shred the door that Claws Ward has used when a kid he had attempted to scare turned out to be unafraid of him. They also take out the garbage, nearly destroying Boo, who manages to get out before they put the garbage in the crushing machine.
In one of the film outtakes, Smitty mispronounces Sullivan's name as "Solomon" and Needleman tries to tell him that his name is "Sullivan," but the two begin quarreling as they end up ruining the scene and making matters worse. Another outtake shows the duo about to shred the door that Claws Ward has used; the door shredder chews the door, but then takes the two on a wild ride across the scare floor and knocks over the crew equipment.
They appear in Mike Wazowski's company play "Put That Thing Back Where It Came From or So Help Me" as Randall Boggs and Fungus respectively, to which the crowd boos at them for their evil roles.