A robot was a mechanical being designed by King Nub which came to life to kill any intruder who entered to Nub's Tomb. The robots, however, were also discovered within the Infernal Machine in Babylon.
Some moved around by levitation and cut people down with sharp blades that spun in a circle. Others were slower, lumbering robots that had scissor-like blades as weapons. There was yet another robot that fired an electrical blast of energy.
Amazingly, the ancient Nub of Babylonian times was able to harness a mixture of electricity and mechanical engineering to operate the robots who continued functioning even up until their rediscovery in 1947 by Indiana Jones.
As dangerous as these smaller robots were, they were nothing compared to the guardian of Nub's crypt. Nub reserved for himself a giant, bipedal robot that could only be activated by inserting a polished ruby, called "Nub's eye," into its mechanical eye socket. The robot attacked Jones by shooting a laser-like beam out of its gemstone eye and also with its clawed hands.
The robot was accidentally animated by Jones who used Nub's part of the Infernal Machine to activate some energy plates on the floor of the tomb. Jones then lured the robot onto them and each time it stepped on them, the robot was electrocuted. After the final time, the robot's ruby eye overheated and its functions shut down altogether.