Brainbug

A Brainbug (sometimes capitalized as BrainBug) is a term used in science fiction, typically referring to a parasitic or symbiotic organism that attaches to the brain of a host. The creature often exerts some form of control over the host's actions, thoughts, or both. The degree of control varies widely depending on the specific fictional work, ranging from subtle suggestion to complete domination of the host's will.

Brainbugs are frequently portrayed as grotesque or alien in appearance. They may be presented as originating from outer space, or from undiscovered regions on Earth. The motivation behind their brain-controlling behavior also differs across fictional narratives. Some brainbugs seek only survival, using hosts as a means of sustenance or reproduction. Others may be part of a hive mind or collective intelligence, utilizing hosts to expand their reach and influence. Still others may have more complex or even malicious goals.

The concept of a brain-controlling parasite taps into common fears surrounding loss of autonomy and manipulation. It is often used as a plot device to explore themes of free will, identity, and the nature of consciousness. The term "brainbug" can also be used metaphorically to describe an idea or influence that is particularly pervasive or controlling.