You've rarely if ever seen so many movie styles and stylistic motifs blended together with such cohesion and sincerity, without a single wink to the audience about how ridiculous it all is.

Because it is ridiculous. The ostensible plot is about a family man/office worker shlub who realises after a prostate exam that he loves taking things into his rectum (esoteric enough for a film, but okay...), but for whom taking things into his rectum becomes an addiction (a bit more extreme, but still fairly conventional...), and who has some sort of superpower where he can draw whatever he wants in there through some sort of suction forcefield/superpower and who we later discover has an entire world up there in the form of a fetid cave system that contains all the objects and people he's taken in.

But the script by Ryan Koch and director (and star) Tyler Cornack not only takes the conceit completely seriously, it remixes it through several filters lifted wholesale from other genres and styles that completely work when they should make a muddled mess of the whole thing.

Chip (Cornack) works in a drab office where the manager is the sort of overeager, everybody's-best-friend type who – with his singalongs and back-slapping, makes you either cringe or drink his Kool aid. Chip seems completely miserable with his life, including that of his marriage to his pretty but disinterested wife Anne and their baby.

But after a routine prostate exam gives him a sensation he wants to repeat – one that's not necessarily conveyed as being remotely sexual, by the way – he turns his attention to innocuous household items like a board game piece, the TV remote, etc.

When he looks askance at the family dog and in the next scene you see his wife putting posters advertising their missing dog up around the neighbourhood, the film reveals that Chip is actually the villain, and when the unthinkable happens and a kid at the local park goes missing (yes, up Chip's butt), he graduates to full-on murder.

We skip forward to nine years later, where Chip has apparently given up taking objects and people into his rectum after the guilt at what he did to the local kid, and he's been going to AA meetings to manage it, his peers having no idea of exactly what he's addicted to.

It's there he meets Russell (Tyler Rice), a grizzled plain clothes detective with greasy hair, a cigarette eternally set in his porn-tached mouth and a leather jacket. Russell's life has fallen apart since his marriage breakup years before and he knows he needs to do something about his drinking.

He joins Chip's AA group and the two men connect when the leader assigns Chip to be his sponsor. Russell is quietly pleased despite not wanting to let his tough guy exterior show, but when he has trouble getting Chip on the phone over the next few weeks, he suspects something.

It's made worse when a kid goes missing from Chip's workplace during a bring your kid to work day. We know Chip has gone back to his terrible old ways and when Russell is assigned to the case, Chip knows he's going to have to be extra careful.

I won't say where it all leads in the last act (physically as well as narratively), because you can barely believe the script goes there, and it's even more incredible that the film still never breaks character.

What is that character? While it's hard to put into words, it's the best example of getting tone completely right on screen you've seen in ages. Chip lives in the world of Mike Judge's Office Space, where colours are washed out and life is an endless series of boring routines, the only thing changing is you getting older.

Russell lives in an 80s cop thriller procedural, all rain-slicked streets, shadowy alleyways and stakeouts in sedans full of cigarette smoke and bad coffee – he even has the cranky, no nonsense chief who demands the case be wrapped up and warns Russell away from the wild theories he's coming up with.

None of which makes Butt Boy a more entertaining watch than many other films – it's not necessarily even a great movie if you're there for an interesting story. But if you're interested in how the mise en scene of creative direction combines to create particular moods and aesthetic atmospheres on screen, this is the most successful example of it in a long time.