Ghost - Like rap song

hi, I am looking for this rap song I used to listen to in high school....all I remember (and is stuck in my head) is this ghost like sound in the background that reps ..the rapper's voice was deep...
THANKS

Okay when i think of "ghost" and "rap" i think of the group "spooks" - they have two songs that sound ghost-like: "karma hotel" and "things i've seen". It's probably not what you're looking for, but i thought it would be a shame in case this was it and I didn't bother to say anything.