The Delirium Brief - Charles Stross

I'm not that far in, but while they've always had an element of horror, with the lampshading of spy novels and the overall wit, the Laundry Files to me are more fun tentacular-horror entertainment than unsettling (though, to be utterly honest, some pretty horrific things happen in them).  Actually, The Apocalypse Codex got to me, but that's legit for some person reasons that made the evangelical pseduo-christian cult be something that is deeply deeply unsettling.

 

This one... well, things start out having gone all Pear Shaped, and Bob is playing damage control after the events... and things get more tangled from there.  I love the jibes at Trump, but without spoilers let's just say that within the first 1/8th of the book I've had an "Oh Fuck" moment.