7. Twitch of the Death Nerve (1971)
Twitch of the Death Nerve is an under-appreciated masterpiece from the inventor of the Italian horror subgenre called giallo. The giallo genre derives its name from sordid Italian mystery novels typically bound in yellow covers (giallo is Italian for yellow). These novels contained Agatha Christie-like tales of murder and intrigue. When Italian filmmakers brought giallos to the big screen they added gratuitous bloodletting, hallucinatory bordering-on-nonsensical imagery, and copious nudity to the mystery plot lines. Mario Bava created the cinematic giallo with his feature The Girl Who Knew Too Much and he returned to the genre for this outing with a new trick up his sleeve: outre gore scenes. Bava's previous films depicted cinematic bloodshed but nothing to the extent of Twitch of the Death Nerve, which includes machetes to the face and a pair of lovers being skewered by a spear in mid-coitus. Death Nerve earns its must-see status because of its profound influence on the slasher genre. Bava broke new ground and paved the way for future horror filmmakers to depict zealous and increasingly ludicrous levels of carnage and mayhem.