Although there's a ton of cool uptempo jazz, very little of it lends itself to Halloween. If, however, you're looking for a spooky-sounding, jazzy instrumental to underscore your run across a darkened parking lot or garage in the rain on Halloween night, check out "On The Loose" by Slowly. I pulled out a sampler CD from 1996 today, and the tune left the same haunting impression it did 22 years ago.