Stuart Gordon's From Beyond (1986) is the purest version of a very specific nightmare: the scientist who believes the mind can be expanded by machinery, and the machine that answers back. Dr Pretorius's Resonator stimulates the pineal gland, and what it reveals is not enlightenment but a parallel dimension of hungry, pulsing things. The film is gleeful and disgusting in equal measure, and its practical effects (the pineal stalk, the melting bodies, the flesh-eating swarm) do something no CGI could: they make the invisible anatomy of the mind into latex and lubricant and light. Released in the same year as Aliens and The Fly, it belongs to a moment when horror decided the body was the most frightening special effect of all.
The chain that follows takes that premise seriously. David Cronenberg is the presiding spirit, and his Scanners (1981) and Videodrome (1983) are the twin pillars: in the first, a drug-induced telepathy becomes a weapon and a medical catastrophe; in the second, a television signal grows a tumour in the viewer's brain. Ken Russell's Altered States (1980) pushes the same idea into sensory-deprivation mysticism, with William Hurt's scientist regressing physically as his consciousness expands. These are not films about monsters from space; they are films about the mind as a place with a geography, and the horror of discovering that geography is inhabited.
What binds the sequence is craft. The colour palettes are aggressive (the hospital green of From Beyond, the cold steel of Scanners, the amniotic reds of Altered States), the sound design hums and throbs like a machine under load, and the effects teams worked in rubber, foam and blood. The result is a kind of visible thinking, the interior made monstrous. Later entries in the chain, from the gooey satire of Society to the digital-body anxieties of Possessor, show that the tradition never died; it just changed tools.
Watch these in order and you can trace a lineage: the machine as forbidden door, the body as its unwilling laboratory, and the practical effect as the only honest way to show what happens when the door stays open.