Lots of murder ballads lurk in the mountains of Appalachia, but the centuries-old “Greenwood Sidey” must rank near the top for creepiness.Long story short: A woman kills her two newborns in a wood, only to have them return to haunt and condemn her to hell. This dark-as-night ditty was recorded in the Child Ballads collection, a 19th-century book of folk tunes from England and Scotland.Anna Roberts-Gevalt and Elizabeth LaPrelle, a pair of performers from the mountains of Vermont and Virginia, respectively, learned the song from Addie Graham, a ballad singer from eastern Kentucky. Their version is fragmented and sparse on details, leaving out many of the verses sung in European versions. We premiered it here, and now the duo have returned with an animated video for the tune that'll make your blood run cold.Filmed by Rebecca Branson Jones, the video is based around a hand-made “crankie”—a long scroll moved slowly through a cabinet—that fills in the rest of the story. The tale is told in stark black-and-white, interrupted by flashes of red for a visceral effect that makes clear visually what is only hinted at in the lyrics. Anna and Elizabeth made the crankie by carving linoleum into block prints. The story remains fragmented, using flashbacks and repeated images utilizing blood-red stains to twist the meaning.In performance, Anna has taken to following “Greenwood Sidey” with an instrumental fiddle tune to relieve the tension. “The crankie makes it more intense,” Anna says. “The lights are off. This lady just killed her children. I’ll play the fiddle for a while after, because people don’t usually want to clap after it. It gives people a chance to breathe, and for us to breathe too.”Mason Adams is haunting Twitter.