Butcher Block is a weekly series celebrating horror’s most extreme films and the minds behind them. Dedicated to graphic gore and splatter, each week will explore the dark, the disturbed, and the depraved in horror, and the blood and guts involved. For the films that use special effects of gore as an art form, and the fans that revel in the carnage, this series is for you.

Very few filmmaker debuts evoke quite as visceral of a response as co-writer/directors Julien Maury and Alexandre Bustillo’s Inside. A brutal take on the home invasion sub-genre that masters the art of building suspense, Inside revolves around a fateful night on Christmas Eve, where a very pregnant Sarah (Alysson Paradis) is stalked and tormented in her own home by a woman dead set on stealing her unborn baby. The simple concept is anything but as Maury and Bustillo infuse the story with tragedy, deep grief, surprising revelations, and a shocking amount of bloodshed.

Long-time genre fans, Maury and Bustillo posed a simple question when penning the screenplay; what if the killer was a woman? In horror, it’s typically maniacal men chasing the women. With the major gender reversal of the antagonist, the writer/director duo then wondered what would motivate a woman to stalk and hunt another woman. That woman didn’t have a name; she was simply credited as “La Femme,” or the woman. And La Femme is one of modern horror’s most terrifying villains, in no small part due to having been played by the intense Béatrice Dalle. The actress had already demonstrated a knack for portraying unhinged yet fierce characters, like the ferocious cannibal Coré in Trouble Every Day. Dalle would reteam with Maury and Bustillo again in their films Livid and Among the Living.

La Femme doesn’t just torture Sarah, ruthless and unrelenting in getting what she wants, but she has zero qualms about slaughtering anyone else that might get in her way. This means that Inside gets extremely bloody. It flows, spurts, and gushes from the wounds inflicted. It really never stops flowing, only increasing to near geyser-like levels in the climax. Because the gore and blood effects were practical, Inside had to be shot in order. Cleaning up the sheer volume of fake blood would’ve proved far too tricky to film out of order.

The special makeup effects team had a lot of work cut out for them. The budget roughly around 2 million dollars, most of it went to the special effects. Knitting needles to the jugular, sewing shears to the groin, head explosions, a self-tracheotomy, and so much more. The team had to mold prosthetics and endless gallons and tubes of fake blood to be pumped through the open flesh wounds. The makeup effects supervisor was Jacques-Olivier Molon, who previously worked on genre films Horsehead and Orphan, and more recently on Mandy. Other notable names from the team include Nicolas Herlin (As Above, So Below, Livid, Leatherface), Sabine Fevre (Among the Living, Silent Hill: Revelation), Pierre-Olivier Thevenin (Jurassic Park, Blade II), and many more.

Christmas Eve doesn’t factor prominently in the plot; it’s another indicator of Sarah’s loneliness and profound grief after the startling opening scene. But there’s an emotional resonance there that connects with the holiday, and the blood red color consistently filling the screen also feels holiday appropriate in a very warped way. Maury and Bustillo unleashed primal rage on screen, and with it a torrent of violent bloodshed. Yet it’s balanced with emotional devastation that pulls it back from exploitation. For those that prefer their holiday viewings without cheer and merriment, Inside is among the very best in extreme French cinema.