if you have a strat, you can get a creepy tone, its not very dark, or deep, but its a high pitched screechy kinda thing. put on distortion, put it on the bridge pickup (at least thats how it is for me) and do some spanish style music, only with more vibrato.

or take the pick and scrape it across the whole fretboard on a string with distortion on, sounds like a plane takin off.

there are so many ways, turn the bass way up, treble way down, distortion, etc.