Little green men were the creatures that were controlling the Lefty robot.
During the episode "Lefty" of Dipper's Guide to the Unexplained, they are controlling a robot so no one would find out about them. During the third test when Dipper tries to see Lefty Robot's right side, Dipper finds out about the little green men controlling the robot. Upon discovery, they consume small, red, glowing cubes while screaming, "The time has come!". One said that he couldn't fulfill the pact because he "had a family", to which his friend replied, "You took the oath!" They commit suicide by swallowing the the red cubes, fall out of the robot, and then disappear after they die. Then the robot self destructs.
They are small, gelatinous green creatures wearing gloves and a belt with a lightning bolt on the buckle. They have relatively large eyes and prominent lips.
- There are a total of 16 creatures shown.