(Every week, in the Retro Rental, James Rocchi recommends a film on disc, download or streaming inspired by what’s being released that week, goings-on in the world, or, really, anything …)

You have the bowl of candy. You have a mix of Nick Cave, Screamin’ Jay Hawkins and the scarier P.J. Harvey songs on the stereo. You’ve carefully razor-cut crescent roll dough and wrapped it around half-hotdog pieces so your hot party snacks look like little mummies. There’s more than enough fake webbing festooning the front light to both warn and entice trick-or-treaters. You’re all ready to enjoy Halloween.

Except, of course, you forgot to get some movies. And that is truly horrible.

Whether you’re just looking for grim background visions as scary visual wallpaper or hunkering in to a movie marathon with the doors locked to shun all the madness, you need movies on this night — and this week in the Retro Rental, we’re picking 21 of the best and the most bizarre on Netflix streaming, Hulu Plus, Amazon Prime Video, Crackle and iTunes so that you can perfect your holiday atmosphere without having to run into some person in a werewolf outfit … or, worse, some werewolf in a people outfit. It’s the Fun-Size Halloween Retro Rental, all for you …

The Battery (iTunes)

One of this year’s best indie horror films, The battery is well worth your while as a micro-budget film with mega-smarts. In the wake of, yes, a zombie apocalypse, two teammates from Baseball’s minor leagues have to survive the ambulatory dead — and each other. Like a strange hybrid of George Romero and John Sayles, The Battery is about character and personality as well as blood and guts …

The Vanishing (Hulu Plus)

Later re-made in America, this Dutch horror film has a deeply creepy set-up … and an even more terrifying resolution. A couple traveling stop at a gas station, and she never comes back. years later, he’s offered the chance to know — and know exactly — what happened to her.

Henry: Portrait of a Serial Killer (Netflix Watch Instantly)

Thanks to this John McNaughton independent classic, I still can’t look Michael Rooker in the eye. Naturalistic, grim and unafraid to show evil at its most banal, Henry still scares precisely because its monsters are all too human.

Monsters (Amazon Prime Video)

A giant monster movie that both works and works as much more, as writer-director Gareth Edwards creates creatures that are both monsters and metaphors when a reporter and an heiress are both caught South of the border where extraterrestrial visitors have crash-landed hard and and crashed our ecology even harder.

Christine(Crackle)

A John Carpenter film, this Steven King saga has three things going for it — Carpenter’s direction, Keith Gordon’s great performance as a nerdy kid who finds a old car that has more than just mileage on its meter, and the classic combination of, as King put it in his book, “Teenage love songs, teenage car songs and teenage death songs.”

The Blob (Hulu Plus)

Not only is the theme song – by Burt Bacharach — a strangely great mambo number, but there’s also Steve McQueen as our intrepid hero and a classic outside-the-box monster film as an amorphorous dollop of hungry protoplasm falls from the stars.

Stake Land (Netflix Watch Instantly)

From Jim Mickle, a nicely-tuned antidote to sparkly new-wave Vampires as a boy and his father-figure-slash-mentor travel through America after a bloodsucker epidemic has wiped the nation out; put Van Helsing and an apprentice on The Road, and you’ll have a good idea of why Stake Land works.

The Descent (Hulu Plus)

Sure, The Descent  is gory, as a group of femal friends on a cave-exploring expedition go off the beaten path and into a hidden darkness full of blind albino flesh-eating cave-people … but it’s also utterly and totally driven by who these women are, giving the film’s terrors a much deeper chill.

Repulsion (Crackle)

Roman Polanski’s brutal, black-and-white chronicle of madness, as Catharine DeNeuve sinks, all on her lonesome, into the depths of insanity; a slow-burner, but very much worth it.

Piranha (Netflix Watch Instantly)

No, not the new boobs-and-butts version — the original, with great fish attacks, a John Sayles script making smart points about Military science and Joe Dante (Gremlins) working for both horrified laughter and blood in the water.

Behind the Mask (Hulu Plus)

A smart, wicked mockumentary about Leslie Vernon (the crazy-charismatic Nathan Baesel) and his quest to be the next big … masked serial murderer. American Idol plus American Psycho, it’s a spooky as it is smart.

In the Mouth of Madness (Amazon Prime Video)

Another, lesser-known John Carpenter film, as an insurance investigator Sam Neill finds out that a best-selling Horror author’s work — and the psychic energy it engenders in his readers — might be leaping off the page all too literally.

Rosemary’s Baby (Netflix Watch Instantly)

Roman Polanski’s best horror film works, much like Black Swan, in no small part because it’s a monster movie where the patriarchy is the monster and urban life the beast’s creepy collaborator …

30 Days of Night (Crackle)

One of those why-didn’t-anyone-think-of-it-before stories, as a group of vampires take advantage of the Arctic circle’s skewed sunrise-and-sunset mechanics to turn a small town into a 24-7 bloody buffet.

The Stuff (Netflix Watch Instantly)

From Larry Gordon — the weird genius behind movies like Q: The Winged Serpent and the screenplay for the first Carrie The Stuff makes for an uneven but unprecedented ’70s horror flick as a new zero-calorie food product consumes those who devour it in an delicious internalized invasion of the body snatchers.

The Bay (Amazon Prime Video)

Barry Levinson — yes, of Diner and Rain Man — was pitched a documentary about the pollution of the Chesapeake bay; Levinson fast-forwarded the concept into this grisly found-footage horror film, where real-life science with a light sprinkling of nonsense makes for grim and grisly nightmares.

House of the Devil (Netflix Watch Instantly)

A delightfully ’80s retro-fest from director Ti West, as a babysitter hired to watch an isolated home has no idea what she’s really being brought on board for; trust us, you’ll never listen to The Fixx the same way again.

Room 237 (iTunes)

A documentary, sure, but it’s also a brilliant examination of the lines between passion and madness, between insight and obsession, as five film scholars share their very different 9and in some cases, very dark) interpretations of what Kubrick’s The Shining is really  about.

Let the Right One In (Netflix Watch Instantly)

The original, not the agreeable-but-less-startling re-make Let Me In, as almost every vampire-film cliché gets upended, age-reversed, gender-swapped and generally mixed up to create something else entirely.

The American Scream (iTunes)

The least scary — but most heartwarming — film on this list, as director Michael Stevenson looks into three very different families’ quest to decorate their homes as temple to the spirit of the season on Halloween — as well as why.

Slither (Netflix Watch Instantly)

From director James Gunn (of the upcoming Guardians of the Galaxy), a near-perfect flat-out awesome funny-fearsome creature feature as wriggling, grisly parasites come to town and stars like Nathan Fillion, Elizabeth Banks and Michael Rooker have to figure out how to stay uninfected, unabsorbed and alive.