These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Nightmare Fuel: He reportedly used no post-processing to achieve the incredibly disturbing, nightmare-inducing voice of The Darkness. Just his voice and a microphone.
The same talent that lets him range from the nasty gurgling of the Boomer to the hair-raising screeching of the Hunter in Left 4 Dead. As well as all the other disturbing zombie noises in the game. And GLaDOS's Anger Core in Portal.
Hell, his music in general can get to this point. Especially in the cases of Fantomas and Maldoror.