What's your favorite dark instrumental piece?

I comment just to STRONGLY PIONATELY AND VIGOROUSLY support the first poster's recommendations. Prokofiev is a maniac and I strongly endorse his music. If I had to mention one piece however, I would mention Totentanz by Franz Liszt, and if I had to post a video link I would choose Enrico Pace, the first poster properly addressed my concerns. If I must offer a personal suggestion, listen to Rachmaninoff's Piano Concerto's. They will deeply satisfy your most intense musical compulsions.