Tom Servo is a red puppet that has a gumball machine (Carousel Executive Snack Dispenser) for a head, a body composed of a toy "Money Lover Barrel" coin bank and a toy car engine block, and a bowl-shaped hovercraft skirt (a Halloween "Boo Bowl") instead of legs.

His arms would spring up and down whenever the clear balloon inside was gripped by Kevin, as shown in pictures from The Colossal Episode Guide or The Scrapbook tape.

The Patrick Swayze Christmas segment shows Kevin in the puppet trench working Tom Servo with bladder in each hand.

Because Servo's head is transparent, chromakeyed images appear projected through it, and thus a second puppet was built for use in the theater segments, entirely spray-painted black.

In the pilot for MST3K, the robot who would become Servo was named "Beeper", who just spoke in beeps that only Crow could understand (similar to R2-D2 and C-3PO from the Star Wars films).

He was an all-silver robot vaguely shaped like the ultimate Servo, with funnel-shaped shoulders, silver rubber tube arms, a plastic flowerpot for a hoverskirt, and a small fishbowl for a head.

The character was absent in K01: Invaders from the Deep, but re-appeared again for the remainder of the KTMA series as the now-familiar Servo puppet with the gumball machine head in K02: Revenge of the Mysterons from Mars.

By mid season 3 an extra cap from another Carousel Dispenser was added just below the "bubble" making Tom's head appear slightly taller and slimmer.

Almost invariably, however, any attempts at confronting danger or displaying his intellectual skill cause him such frustration that he ends up crying, often needing consolation from Joel or Mike.

He does have a good understanding and intellect in spite of his sensitivity and frustration, and revealed in the episode "The Gunslinger" that he's able to teleport at will, even though he only demonstrates this on rare other occasions.

In Season 13, where the Satellite of Love set is green screen, Servo's head is permanently clouded to avoid chroma-key problems.