The Machine
Ah, the Machine. Particularly scary because the "M" is capitalized. That tells you it means business.
The Machine, which is the brainchild of Count Rugen and was probably commissioned by Prince Humperdinck, tells us a bit about both men.
First, it points to their extreme cowardice. This shared trait is flagrantly on display later in the movie, once when Rugen turns and runs when confronted with Inigo and his famous death threat, and again when Humperdinck drops his sword out of fear of fighting Westley.
But in terms of the Machine, you've got one guy—Rugen—who invents a device that takes another human being almost wholly out of the equation. All you have to do is move a lever and the victim suffers immeasurable agony. If he's going to be a jerk and torture people, the least he could do is own it, right? Get in there a bit and get his hands dirty?
And then, when Humperdinck blows a gasket and runs into the Pit of Despair, rather than fighting Westley like a man, he uses the Machine to do his dirty work.
The second thing it tells us is that they are awfully uncreative when it comes to naming torture devices. "The Machine"? Wow, hope it took less than an afternoon to come up with that one…