It arrived with little fanfare, practically in secret; a Z-list horror film with the unassuming title The Evil Within recently surfaced on Amazon’s video-streaming library, left to molder alongside such little-seen cannon fodder as Stake Land II and It Lives in the Attic. To the untrained eye, it would look like another helping of half-baked schlock, cranked out over a couple of weeks in pursuit of a quick paycheck. But upon further inspection, just beneath the outermost layer of synthetic goo and foam-rubber prosthetics, there lies a passion project built on a foundation of uncommon artistic commitment. Far from a fly-by-night cash-grab, The Evil Within represents 15 years’ worth of effort, standing today as a testament to its creator’s singular mad ambition.

A recent item in the Hollywood Reporter laid out the whole extraordinary account, a bizarre showbiz footnote that’s part cautionary tale and part inspiring DIY triumph. Andrew Rork Getty, scion of the Getty oil dynasty, set out on a quixotic journey in 2002: he’d drafted the script for a horror film based loosely on a series of nightmares he’d personally had, and intended on using as much of his own fortune as necessary to bring it to life. Never one to let a little thing like inexperience stop him, Getty rounded up a crew of actors with no idea what they were getting into and dove into shooting on what was then titled The Storyteller. Production ultimately stretched out over the course of five years, progressing in fits and starts as Getty devised elaborate custom camera rigs, pricy original sets and, in one instance, a large animatronic octopus designed to play a drum kit.

After he called a wrap on shooting, Getty continued to obsess over perfecting each and every frame of this labor of love. He converted one of his mansion’s many rooms into a post-production suite, where he spent untold years on intricate in-camera special-effects techniques. Producer Michael Luceri estimates Getty’s personal expenditure on the movie somewhere in the neighborhood of $5m, a figure that left the heir in financial ruin. His story came to a tragic end in 2015, when he died at age 47 from a hemorrhaging ulcer brought on by a long history of recreational meth usage. He wouldn’t live to see the completion of his life’s work, but his absolute, unmatched devotion to the project shines through in the now-available finished cut.

“It’s terribly sad that he had to leave us so prematurely, such a fascinating creative mind and a great guy,” the editor Michael Lucceri said. “It would have been nice for the filmgoing world to see his evolution as a film-maker. But now The Evil Within will be his legacy piece.”

Make no mistake, The Evil Within is very clearly the handiwork of a rank amateur under the influence of powerful narcotics. The film was horrifically ill-advised from the very start, working from the premise of a man with learning difficulties who commits grisly murders on the commands of his reflection in an evil mirror. Characters appear and vanish without warning or explanation, long surrealist interludes go nowhere, and the plot constantly veers into tangents that appear to bear little relevance to the rest of the film. Even during the brief flashes in which Getty’s script makes some semblance of sense, the finished product plays like an unholy fusion of A Nightmare on Elm Street and the fictitious “Simple Jack” from the showbiz satire Tropic Thunder. Needlessly complex editing schemes betray the fact that the film was pieced together from whatever scraps of footage Getty deemed usable. Listen closely, and you can hear him muttering “Whatever, we can fix that later” in between every take.

And yet the herculean efforts poured into this film lend it a certain undeniable charm. The total lack of studio supervision combined with Getty’s monomaniacal drive and technical knowhow resulted in some truly outré horror, material he simply couldn’t have gotten away with under the auspices of a larger production. Even when they don’t seem to serve any larger narrative or stylistic purpose, Getty’s wild experiments with the form command respect; in one scene, his camera zooms through a gerbil tube into the plastic tank for an extreme closeup of the critters, and in another, it seamlessly swings in and out of a mirror. And the scares Getty dreamed up were several shades weirder than anything a legitimate financier would’ve allowed, from a succubus with pendulous breasts hanging off her back to a screaming woman with two smaller mouths where her eyeballs should be. Getty’s approach often lacks focus, but when his scares connect, they persist for many sleepless nights afterward.

Getty’s long, troubled path through production has yielded one of the surefire cult objects of tomorrow, in no small part because its larger-than-life background has complete sincerity at its root. Lise Romanoff, CEO of The Evil Within’s distributor Vision Films, said she admired Getty’s nothing-to-lose belief in his concept and abilities: “What attracted me to this film was … how [Getty] painstakingly made sure every frame of the film was perfect, and did almost all in-camera special effects. That kind of meticulous work is not done today on most independent movies.”

Even when they come from an eccentric millionaire high on his own power as well as actual drugs, displays of earnestness on this level strike a chord with viewers. Ed Wood’s lovingly made, hilariously incompetent Plan 9 from Outer Space still plays to rowdy crowds at midnight showings – perhaps 50 years down the line, trash connoisseurs will hold Getty in similar esteem.