Gillian Anderson and David Duchovny in “The X-Files.” Photograph from Moviestore Collection / Shutterstock / REX

Certain responses are guaranteed. In biology class, there was always some jokester who would try to gross out his lab partner by hiding dissected frog parts in his or her desk—usually hers. The girl would open a candy wrapper only to find a frog’s eye staring back at her. Advances in special effects have enabled filmmakers to elevate silly pranks into schlock horror. HBO’s campy anthology series “Tales from the Crypt,” also syndicated on Fox, dangles a buggy eyeball in almost every episode, topping a cannibal platter of guts, stumps, and slimy gunk. Its Grand Guignol doesn’t stick to the mind. Playing with one’s food and making a mess is easy. What’s hard is giving shape to the shadows on the ceiling—creating horror not out of human meat but out of the unresolved business of the unconscious. “The X-Files” (Fox, Fridays), which is the work of Chris Carter, employs scare tactics—blood spitting from a face slapped by an invisible hand, a locust-like plague infesting a courtroom—but it doesn’t let them upstage its speculative purpose. Each episode is a mood piece—a queasy odyssey. It’s television’s first otherworldly procedural. Although its ratings have been in the basement, “The X-Files” has been building a cult audience and has the makings of a classic. (The show has been renewed for a second season.) “The X-Files” is as scary as “The Twilight Zone,” and much sexier.

Like “The Twilight Zone,” “The X-Files” expresses a national unease, which helps explain its hold on our nerves. “The Twilight Zone,” first broadcast in 1959, was the dark negative of the sunny snapshots of suburbia shown on sitcoms like “Ozzie and Harriet” and “Leave It to Beaver.” Created by Rod Serling, who also acted as its host, the show served as a night watchman to the anxieties of the atomic age. It presented worst-case scenarios of what might happen if the launch buttons were pushed: neighbors beat on the doors of bomb shelters closed to outsiders; Norman Rockwell villages became ghost towns, a tattered calendar telling us when time stopped; on bare plains, survivors shrivelled in the sun like bugs under a magnifying glass. Whether the threat was missiles or flying saucers, our skies were not safe. Other planets offered no refuge, as astronauts found themselves wriggling in air, tweezered between giant fingers.

The cardboard construction of “The Twilight Zone” didn’t cheapen its sense of dread; it functioned as thin insulation against the abyss. The show’s very lack of production values promoted a stark-bare allegorical staging. I remember having nightmares over an episode in which doll-like characters were trapped in a barrel, verbally abusing one another for what seemed like eternity—a pocket version of Sartre’s “No Exit.” (Hell is other puppets.) That toy barrel, like the show’s bomb shelters, reflected a bunker mentality. The question posed by “The Twilight Zone” was: Who will survive the next blast? And will survival be anything more than death warmed over?

The Cold War is absent from “The X-Files,” replaced by a more cosmic paranoia. The show reflects the end of the millennium, the flip side of the New Age. Beneath the soothing cover of incense, mantras, and Tibetan chants, rude beasts are awakening—Gnosticism reborn. The term X-Files refers to hush-hush, top-secret F.B.I. case studies of paranormal activity. Investigating new outbreaks are the F.B.I. agents Fox “Spooky” Mulder (David Duchovny), a believer, and Dana Scully (Gillian Anderson), a skeptic. Their partnership achieves a rare parity between the sexes, a personal regard shown in subtle body shifts and a steady rebound of eye contact. They’re more than ghostbusters. All escapees from the netherworld are in their jurisdiction, be they vampires, poltergeists, astral projections, firestarters, telekinetics, satanic cultists, psychic surgeons, alien abductees, possessed animals, replicants, reincarnated spirits, shape shifters, or local chapters of the international brotherhood of zombies. Occult signs abound. Pentagrams. Crop circles. Crucifixes. The show’s Sherlock Holmes satisfactions derive from its forensic zeal in the face of garish horror, its refusal to be ruffled or bumped off course. This refusal also accounts for the show’s deadpan humor, as each eruption in the energy field is met with dry-ice understatement by Mulder or capped by an inspired sick joke. (At the end of the firestarter episode, the human torch—sealed in a hyperbaric tube, his body blistered with burns—was asked by a nurse if there was anything she could get him. Turning his charred face to the camera, he said, “I’m just dying for a cigarette.”)

What’s distinctive about “The X-Files,” apart from its ingenious story lines and gun-swivel camerawork, is its suffused atmosphere. Shot in Vancouver, the show’s exteriors seem familiar yet anonymous—muted. David Lynch wrecked the trance of “Twin Peaks” when he abandoned all interest in even a quaint semblance of normality and began to strobe the screen in a fit of expressionism. (His feature film “Twin Peaks: Fire Walk with Me” was even trippier.) “The X-Files” doesn’t make the mistake of elevating its sensibility at the expense of its subjects. It takes time to seep into its surroundings. An episode about a bisexual succubus stalking the disco scene evoked the warehouse purgatory of the porn director John Leslie’s “Catwoman” films, with their deep blues, prowling shadows, and industrial din.

Once an episode earns your faith, no avenue seems too far out. One outstanding “X-File” episode began with a camera pan of suburban back yards, across isolated squares of pasture. A young girl clutching a stuffed animal draws the attention of a passing couple, who follow her into her back yard. On the swing set, her father sits slumped, his back to us. In his neck are a pair of puncture wounds. “Daddy?” No answer. Daddy’s been drained of blood. Vampires? Cattle mutilators upgrading to human prey? No, this blood tap proves to be the by-product of a cloning experiment that resulted in a spate of bad seeds. All the female clones were named Eve and were endowed with extra chromosomes that made them super-smart, super-strong, psychotic, and prone to suicide. (There’s an amazing shot of all the identical Eves posed for a group portrait—at a swing set.) The episode ends with the last remaining clones, Eve 9 and Eve 10—telepathic twins, played with spooky calm by sisters Erika and Sabrina Krievins—imprisoned in an institution for the criminally insane, an iron dungeon fit for Hannibal Lecter. (Visitors are issued panic buttons.) They appear to be there for the duration. But the last shot is of their clone mother, the Eve of Eves, come to claim her daughters. “How did you know I’d come for you?” she asks. Eve 9: “We just knew.” Eve 10: “We just knew.”

Nothing is put to rest on “The X-Files.” The open-endedness of the Eve episode and others indicates not only the untrappable nature of these forces but the show’s refusal to pronounce final judgment. Where “The Twilight Zone” was wrapped tight, everything tied together with an O. Henry twist, “The X-Files” is suspended. Its adversaries aren’t evil; they’re “genetically driven”—damaged from within. Absolution was even granted to a serial killer on death row, played by Brad Dourif as if he himself had been kept in a box. Claiming that he could channel the voice of a kidnap victim, the killer tried to cut himself a deal: I help catch the kidnapper, you spare me the gas chamber. As Dourif dialled into different psyches, he worked his face like a quick-change artist—you could see his pale features bubble and form lumps before they set into the face of someone new. What made the performance more than a technical feat was the passionate overflow he brought to his plight—his redneck fury to hold on to the last inch of life. In league with the dead, he had the cracked karma that Norman Mailer claimed for Gary Gilmore.