While this isn't the strongest giallo I've seen, BLACK BELLY OF THE TARANTULA's main concept is super nasty.
A killer is using a paralyzing agent to "freeze" his victims before cruelly stabbing them. Yes, they are paralyzed and awake as he carves into them. Giancarlo Giannini plays the detective on the case - Inspector Tellini.
There are many stylish elements in the film and the Argento and Bava influences are very evident. I believed the story was rather strong for the most part, but in looking over other reviews, it seems to garnish some hate for some reason. I'm not sure why. People were growling about wanting their time back and how the twists were silly. However, I'm of the opinion that these just are not giallo lovers and they don't get the gag.
This isn't a "straight slasher". It's a giallo and a good one at that. A fun crime drama mystery with some great set pieces, cool style, and a solid story!
I watched SHORT NIGHT OF THE GLASS DOLLS afterwards and heard a very similar soundtrack along with the lovely Barbara Bach's lovely face. Ennio Morricone used a similar "breathy breathing woman" for the soundtrack to each film. Maybe he crafted both scores at the same time to expedite the situation....and payments. :)