Every week, we spotlight a kill that we just can’t get enough of. This is Kill of the Week.

Masterpieces like Halloween and Friday the 13th may have popularized the slasher sub-genre, but the origin tale of the body count film dates back many years prior. Bob Clark’s Black Christmas directly paved the way for Halloween, for example, while many consider Hitchcock’s Psycho to be the first true slasher film.

And then there’s Italian filmmaker Mario Bava’s Bay of Blood (aka Twitch of the Death Nerve), unquestionably one of the earliest and most influential slashers of them all.

In the 1971 film, which predates Friday the 13th by nine years, the body count rises in the wake of a rich countess being murdered, setting off a race to see who’ll inherit her estate. The gory mayhem found in the movie was very uncommon at the time; watching it back today, it’s clear that it laid down the blueprint for the American slasher film.

Of particular note, Bay of Blood was completely ripped off ten years after its release by 1981’s Friday the 13th Part 2. Two of the standout moments of brutality in Bava’s film were directly copied by the second installment of the Friday franchise, including one wherein the killer whacks a machete directly into the face of an unlucky man.

And then there’s the double slaying of a young man and woman who are speared in bed while having sex. The killer slams the spear into the woman’s back, driving it straight through both of their bodies and into the floor below. They both briefly writhe in pain before dying, spending their final moments cruelly joined together by the spear.

The kill in Friday Part 2 plays out almost exactly the same way (though the man is on top this time around), right down to the tip of the spear slamming into the floor.

Bava passed away in 1980, never knowing just how influential Bay of Blood was.