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Stranger Things’ newest villain is as old as Dungeons & Dragons itself

A brief history of the genus illithidae

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A mind flayer makes a psionic attack on a group of adventurers. Tom Wham/Wizards of the Coast

Season 2 of Stranger Things dropped on Netflix late last week, and many have already marathoned the entire thing. Critics have lauded the sequel, especially for how it expands the storyline and ups the stakes with a wider, existential threat.

What follows includes major spoilers for the second season of Stranger Things.

The new season also introduces a brand new villain to the franchise, a vicious creature from the Upside Down called the mind flayer. The first episode of Beyond Stranger Things, a Netflix-produced after-show, goes in-depth on the creation of this new creature.

While the demogorgon was an exceptional main antagonist for season one, the beast was simply a mindless killing machine. For season two, series co-creators Matt and Ross Duffer needed something that was capable of higher thought. The solution was something that they originally called “the shadow monster,” a massive creature drawn from the H.P. Lovecraft school of gigantic, otherworldly horror.

“It’s something, often from another dimension, that you don’t understand,” said Matt Duffer. “It’s something beyond human comprehension.”


The Duffer brothers knew that they wanted the shadow monster to rely on telepathic communication, that it would act as the central hive-mind exploiting the rift between our world and the Upside Down.

But months into their research, they still didn’t have the intimate, first-person details that would bring the creature the life. That’s when the team stumbled upon the mind flayer, an obscure monster buried inside Dungeons & Dragons’ original Monster Manual.

The stat block for the tentacle-faced mind flayer indicates that it is rare for adventures to encounter it in the wild.
The mind flayer, from the 1979 version of the Monster Manual for Advanced Dungeons and Dragons by Gary Gygax. This iconic illustration is by David Sutherland, who also illustrated the Tomb of Horrors module.
Wizards Of The Coast

“Mind flayers are found only in subterranean places, as they detest sunlight,” wrote Gary Gygax, the co-creator of D&D. “They are greatly evil and consider the bulk of humanity (and its kin) as cattle to feed upon.

“These monsters speak only their own arcane language and several other weird tongues — purportedly those of terrible races of things which dwell in regions of the subterranean world far deeper than mankind has ever ventured. It is also rumored that these monsters have a city somewhere deep beneath the earth. ... Its skin color is a nauseous mauve, its tentacles being purplish black. A mind flayer’s eyes are dead white, no pupil being evident. The three long fingers of each hand are reddish, but the hands are mauve.”

Also known as illithids, mind flayers have remained a vital part of D&D lore since 1977. They also featured prominently in Volo’s Guide to Monsters in a revised portion of lore first revealed here on Polygon.

Stranger Things season 2 is now streaming on Netflix.

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