I genuinely think the top-tier books in this weird subgenre are the ones that go for the throat instead of just dangling mistletoe over a jump scare. 'The Stupidest Angel' by Christopher Moore leans hard into comedy, but the parts with the zombie Santa still give me the creeps every December. Then there's 'Hark! The Herald Angels Scream,' that anthology edited by Christopher Golden – some of those stories are just bleak, like one where a department store elf is way more than he seems. It's the contrast that gets me; you're reading about tinsel and eggnog, and then suddenly there's something ancient and vicious lurking in the snow.
My personal favorite, though, is a novella called 'Secret Santa' by Andrew Shaffer. It starts as this funny office satire, but the cursed Yule gift the protagonist receives? It taps into this deep, pagan-level dread that feels older than Christmas itself. That's the sweet spot for me: when the terror isn't just a monster in a red suit, but something that uses the holiday's own imagery and forced joy against you.