How do you know this soundscape represents a swamp, other than the title? Mainly from the buzzing insects. The mud is implied by occasional "sticky" footfalls. Why is the mud black? Well, because the title says so, and because it's nighttime, as you can tell from the crickets. Unlike most of Plate Mail Games's background loops, this one also has touches of "music" in the form of sustained, relatively high-pitched tones. The sound is sometimes almost like an electrical hum. These long notes add a touch of mystery, making this an excellent loop to play under any swamp scene, such as (but not limited to!) a visit to a black dragon's swamp in a fantasy RPG or the Louisiana bayou in Call/Trail of Cthulhu scenarios.
[5 of 5 Stars!]