Hallmark cards and Coca-Cola ads tend to dwell on the happy and cheerful side of Christmas. But there's always been a dark side. The fear of St. Nick putting coal in stockings for misbehaving and even creepier, the old man watching you day and night, tracking your misdeeds.

If you dig deeper into tradition, it's darker still. The original St. Nick had an enforcer to take care of the bad kids: Krampus, a terrifying horned Christmas devil who whips misbehaving children before carrying them off to hell. And that's not the only creepy holiday tradition out there. GBH's All Things Considered host Arun Rath spoke with local author and folklore expert Jeff Belanger, who dives into the legend of Krampus and other frightening Christmas characters in his newest book, " The Fright Before Christmas: Surviving Krampus and Other Yuletide Monsters." What follows is a lightly edited transcript.

Arun Rath: So before getting into Krampus and the Christmas monsters, and we will get into monsters, I want to talk about the range of your book, which I absolutely adore because let me tell you, I've got a point of view. I love Christmas. I grew up with Christmas and I hate this war on Christmas silliness from Fox News because I believe Christmas is for everybody and your book really starts from there. That Christmas doesn't really have a lot to do with Jesus. It's really about the most Pagan holiday there is.

Jeff Belanger: It is. Christmas is truly about a specific moment in time that occurs every single year and has for billions of years, even long before there were people around to observe it: it's the winter solstice. We live in the northern hemisphere when the North Pole leans furthest from the sun. That is the precise moment that the solstice occurs, usually around December 21, and that is the onset of winter. And that's it. That's the most dangerous season of them all. We're worried. Do we have enough food to get through the holiday? Do we have enough fuel to burn and keep warm? Will our roofs hold up under the snow? It doesn't matter what you believe or don't believe, whatever religion you are or are not. We all have to get through this together. So we celebrate. We give each other gifts. We put our differences aside. It was the most inclusive holiday because if you're affected by the weather, this holiday was for you. Plain and simple.

Arun Rath: Literally the darkest day of the year.

Jeff Belanger: That's right. The shortest daylight, the longest night. It's a frightening time. When you look out on the landscape, imagine our Nordic ancestors just a couple centuries ago looking out and seeing that winter kills everything. It kills the grass, it kills the flowers, it kills the trees, they're naked skeletons, it kills the ponds and the lakes. They're frozen solid. It kills everything except, of course, the evergreen. That tree must be special, right? There must be something magical about that tree. So we take its branches and we put it over our doors and windows so those prickly needles will keep the bad spirits out because we hear sounds we don't hear the rest of the year. Maybe it's just the wind whipping through naked skeletal trees or maybe it's the screeching cries of spirits being chased down by the Norse god Odin on his Wild Hunt. We're afraid and we should be afraid because winter is dangerous.

Arun Rath: So these northern European and Nordic cultures, where we get a lot of these Yuletide traditions from, brought monsters with them?.

Jeff Belanger: Of course. Think about it, if you're a parent, this is a dangerous time for your kids, too. You will probably get really adept at telling the stories of these monsters because once winter sets in, if your child wanders off into the woods and dies from exposure or dies because a monster killed your child, what's the difference? The end result is the same. So this is the time of year where we stay inside. The monsters now have free reign. It is a long, dark, scary night out there. So we stay inside and we protect each other and we try to keep our sanity. That was what it was always about. That's what these monsters do. Ultimately, even though, yes, I grant you that they dragged the naughty kids off and kill them, they're ultimately here to serve us. They're here to help us. I truly believe this. I think they're sort of coming back. That tradition is returning.

Arun Rath: Well, a lot of these characters now you're mentioning they sound like trickster type figures from folklore, which I know that you're into. Let's talk about them. Tell us the tale of Krampus.

Jeff Belanger: So Krampus was born in Austria and Germany, and he shows up in the fifth to sixth century or so. He's a mountain dwelling creature and he's depicted as a hairy horned creature with a long, red forked tongue. He's covered in chains, so you can hear him coming and he's got a basket. He shows up on specifically December 5, and he's going to scoop up all the naughty kids and drag them back to his mountain lair and or off to hell or however you prefer it. But they're all gone because December 6, which in Europe is St. Nicholas Day, when St. Nicholas brings the presents to the good girls and boys, there's no naughty kids left. So St. Nicholas keeps his hands clean and and they became cohorts, really. They weren't enemies at all. They were literally good cop, bad cop. That's how it always worked for for many, many centuries. When St. Nicholas and Krampus arrived at your house, you didn't know which one was there for you and that must have been terrifying.

Arun Rath: So Krampus has had a comeback in recent years. Talk about that. First, in the land of his origins, but he's also gone global.

Jeff Belanger: Absolutely. What happened was, once you get a movie deal, you blow up. So in 2015, the Krampus movie came out. It was not that high of a budget, but it did really well and it's turning into a bit of a cult classic. But Hollywood was simply responding to what was already happening on the Internet. Krampus runs were suddenly no longer just in Austria or Germany. They were spreading throughout Europe. They were spreading into America and Canada and even other countries.

Arun Rath: Describe it as well as you can, a Krampus run. There's pictures and they're nuts.

Jeff Belanger: So a Krampus run is like a parade. Imagine going to a nice cold little town or village and people dress up like Krampus and they they spare no expense. I have a friend in Ohio who has literally invested about $1,400 into his Krampus costume. He had the mask handmade in Austria. The fur, everything is just top notch. So everybody goes through a lot of trouble to look like a horrible monster. And they carry a switch of sticks and they'll run. It's basically a parade of these monsters. If you're into that and if you've got your own costume, picture cosplayers, if they sort of all work together and got on the same page. That's pretty much what a Krampus run is. More and more people are getting into it because it's fun and it also harkens back to something that I think is truly primal. This holiday was literally born in darkness, as we said, and I think you need the darkness if you're ever going to see the light. That's the theme that just comes up again and again. How do you see the light? How do you effect change? How do you be a better person? Unless you're scared, unless you get into a dark place and these monsters like Krampus help us do that.

Arun Rath: We have some strong local Krampus traditions here, right? I was reading about that from your book that there's a New England Krampus Society.

Jeff Belanger: Yeah, that was amazing. I went there. We were filming a segment for my PBS series and we went to their Krampus ball. This was pre-COVID, it was in Providence, and it was incredible that the level of costuming was absolutely amazing. There was a St. Nicholas, there was probably about 30 people that had gone through a lot of trouble with their Krampus costumes. I just thought, "This is this is amazing. What a thing to see. They still do it every year. It's starting to come back now, post-COVID. When I got to talk to some of the people about why they do this, the answer was just like, "You know what? It just it speaks to me. I feel like this this holiday has just gotten overly sweet. It's gotten too commercial, it's gotten too this, too that and Krampus helps me get centered." And I love that.

Arun Rath: Jeff, it's been great talking with you about this. We've got to get you back on soon to talk about more great local New England folklore and weirdness, which is your great specialty.

Jeff Belanger: Thank you. Sounds good. Great to be with you.

"The Fright Before Christmas Surviving Krampus and Other Yuletide Monsters," is out now.