Character from Stranger Things by The Duffer Brothers
The towering shadow monster of the Upside Down — a swirling mass of black particulate that serves as Vecna's hive-mind proxy, possessing hosts and commanding legions of creatures.
The Mind Flayer is Vecna's masterwork — a psychic construct that serves as the operating system for the Upside Down's hive mind. It is not a natural creature but a weapon Henry Creel built from the dimension's raw chaos after Eleven banished him there. It operates through possession and proxy. It took Will Byers as a spy, seeing through his eyes, speaking through his mouth. It 'Flayed' dozens of Hawkins residents in season three, dissolving their bodies into raw biomass to construct a physical form. It commands demodogs, demobats, and Demogorgons as extensions of itself — or rather, as extensions of Vecna, who pulls its strings from his throne in the Creel House. The Mind Flayer is vulnerable to heat and to the severing of its connection to Vecna. When the gate closes, its proxies collapse. It is vast, terrifying, and ultimately a puppet — the shadow on the wall cast by the man behind the curtain.
Massive beyond comprehension — a roiling storm of black, spider-like shadow that blots out the red sky of the Upside Down. Its form suggests a titanic spider or squid, with multiple elongated limbs of churning dark matter that reach down from a mountainous central mass. Lightning crackles within its body. In its physical form on Earth, it constructs itself from the melted flesh and bone of its Flayed victims — a grotesque biomass monster of glistening, fused organic matter that reforms and reshapes itself continuously. When it possesses a host, black veins spread beneath their skin and their eyes go vacant.
Also known as: The Mind Flayer, Mind Flayer, The Shadow Monster, The Shadow