The holiday season is often celebrated with traditions of joy, generosity, and storytelling, including the long-standing custom of sharing ghostly tales during Christmastime. As the classic lyric reminds us—“there’ll be scary ghost stories and tales of the glories of Christmases long, long ago”— these chilling narratives have been a part of the season’s folklore for centuries. From eerie apparitions to unexplained phenomena, the season of goodwill has a darker, mysterious side woven into its history. Are they only holiday legends, or real ghosts of Christmas past? On this Friday the 13th, here 13 haunting Christmas tales as chilling as the winter air.

You know Bigfoot and Nessie, and Yeti and Dogman… but do you recall any of these 10 lesser-known cryptids? From the mysterious jungles of Southeast Asia to the depths of the Congo Basin, these bizarre and rare cryptids aren’t nearly as famous as their legendary counterparts, but they defy explanation all the same.