PHOTO @ CINEDIGM

I think “The Outwaters” may set an all-time record for the fastest — and most complete — transition from banal to extreme. One minute, it’s a languid record of a camping trip; the next, it’s nearly incomprehensible, cosmic horror.

This film may induce whiplash. And, perhaps, nausea. Proceed at your own risk. If you’re a fan of outre cinema, though: Strap in.

Presented as footage found after a disappearance, “The Outwaters” teases the horror to come with a cold-open 911 recording; we are promised, within moments, that none of our characters are going to make it out alive, and given an auditory glimpse of the madness that awaits them. After that moment, though, there’s a long stretch of … well, not much at all. Four friends head into the Mojave Desert to camp and make a low-budget music video.

This sequence undoubtedly goes on a bit long, but it also lulls the audience into a sleepy complacency; whatever’s going to happen, it seems, will probably happen slowly.

Instead, with the thwack of an axe and a bobbing flashlight beam, everything passes into the uncanny in an instant.

The rest of “The Outwaters” is a marathon of chaos, as time, space and reality are thrown out the window. It’s not clear to the viewer precisely what’s happening from this point on. In one minute, the characters have passed into a nightmare version of a family home; in the next, they’re trapped in a tent and it seems to be raining blood. In one moment, the camera captures a scene from earlier in the movie, viewed through some impossible wormhole; in the next, the vague outline of an incomprehensible monster is traced by that flashlight beam.

If you’re waiting for an explanation, you won’t get one. And for more mainstream audiences, “The Outwaters” will be a bridge too far on several levels — chiefly how little of the back half can actually be seen. It’s a film that works on audio, suggestion and dread.

It is, however, terrifying — and masterful. Writer, director and star Robbie Banfitch is unabashed in both the control he exerts over the film’s chaos and the extreme places he’s willing to go. It is undoubtedly only for certain audiences; for those hardy enough, “The Outwaters” is remarkable.

My Rating: 8/10

“The Outwaters” opens today at the Harris Theater.