Sophon

The Sophon is a minor antagonist of Remembrance of Earth’s Past Trilogy, a sci-fi novel written by the Chinese writer Cixin Liu. A supercomputer made from a single proton, it is sent to Earth as the mouthpiece and espionage unit of the alien invaders known as the Trisolarans. Although possessing little, if any, sign of autonomy in Three-Body Problem and The Dark Forest, in Death's End it gains a physical form and displays behaviors, even emotions, that are disturbingly human.

Three-Body Problem
Upon discovering Earth as a habitable planet of moderate climate and unchanging day length, the alien civilization Trisolaris immediately plans on invading Earth, eager to leave the harsh and volatile triple star system they call home. However, their preliminary study has shown that mankind's technological development far outpaces theirs, and while Trisolaris still holds technological supremacy at the present stage, during the flight of the invasion fleet (which would take 400 years to reach Earth), human technology would have surpassed Trisolaris, which would spell certain doom for the fleet. Thus, the Sophon project is launched as a countermeasure to this: a lock that bolts down Earth's technological progress until the fleet arrives on Earth.

The creation of the Sophon involves "unfolding" a proton's extra dimensions, turning it into a sheet the width of a planet. Circuits are etched onto the sheet using strong interaction force before folding the sheet back into a proton (now a quantum computer). Because of its nature as a subatomic particle, it can be accelerated to light-speed and arrive in the Solar System in advance, carrying out it's purpose: to sabotage Eath's technological development.

Upon reaching Earth, the Sophon scrambles every particle accelerators, forcing them to give false and inaccurate results each time a collision experiment is conducted. Aside from this main task, the Sophon also is responsible for spying on mankind, and getting human traitors on Earth in contact with the Trisolaran fleet. It is not until the traitors' base are raided by government forces does the world know the presence of the Sophon. The moment globel leaders and military realize this, the Sophon projects the words "You are but bugs" onto their retinae to rub in their face the fact that mankind has already lost all hope when the Sophon comes into place.