The Screwheads are a race of humanoids whose name is derived from the huge screws in their heads. They are short in stature, with yellow skin and beady blue eyes. Their tongues are forked like a snake's, and they appear to have almost webbed feet. Their clothing consists of a belt with a long loincloth or jacket attached.
The Screwheads' home planet had been conquered by the Irken Empire and been converted into the Conveyor Belt Planet, which facilitates the shipping of packages to other planets via wormholes. The Screwheads themselves were enslaved as well, and now toil endlessly on their own planet, shipping packages under threat of torture by the Slave Drivers. However, once Almighty Tallest ZIM came into power, they were freed, and their planet was restored to its pre-conquest state.
One of the Screwhead laborers, Smikka Smikka Smoodoo, once attempted to start a rebellion against his Irken oppressors, but the closest he got before he was shocked by a Slave Driver was switching the labels on two packages. Ironically, Smikka did cause a chain of events that may have led to the series finale, Invader Dib. The packages he switched caused Invader Tenn to receive malfunctioning SIR Units, which destroyed her base and caused the Meekrob to discover her and hold her hostage, starting a war between the Irken Empire and the Meekrob, and a rescue mission to retrieve Tenn. This war resulted in ZIM claiming the Irken throne, liberating the Screwheads and restoring their homeworld to prominence.
It is unknown if the cranial screw for which this species is named is a natural feature, or if it was imposed by the Irken Empire. The latter theory is supported by its similarity to the brain probe Zim uses to monitor Nick's "happiness center" and to the probe that Zim used to help control the emotions of the Santa suit.
Emancipation by the Irken Republic[]
After the Screwheads assisted Zim and his forces in the defeat of Dib during the Meekrob War, Smikka's people were liberated by the now peaceful Irken society. The Conveyor Belt Planet was restored to its pre-conquest state, and Smikka was named the ambassador to the Screwhead race.