It's hard to imagine an infernal SCP being all that interesting after the hilarious and bizarre Ice Cream Hell, and sometimes, the presence of elements from traditional mythology and spirituality kind of clashes with my own view of SCP's as anomalous but not necessarily "magical" phenomenon. 3667, however, undergoes a pretty fun and unique story progression with an almost outrageous conclusion. It begins as a fairly straight "portal to hell" scenario, with an extradimensional subterranean space populated by an assortment of nasty demons and tortured, perpetually regenerating humans.

The demons come in quite a nice variety, including toadlike beasts that function more like living iron maidens and massive, many-legged worms that feed from a river of dissolved bodies only to defecate the victims alive and whole. Classic!

Some of these entities, however, prove a tad anticlimactic...and deliberately so. The demons seemingly in charge of bartering for human souls, for instance, display no actual ability to make good on their end of the deal and will try to weasel out of it if anyone surprisingly takes them up on their offers. Exploration logs reveal that modern weaponry can pop the denizens of hell like sad water balloons, and soon enough, the legions of the underworld are hiding in fear from a few Foundation operatives with guns. If this is indeed really "hell" or at least the thing that inspired our concept of it, it's been overhyped to an almost pitiful degree.

Eventually, demons come to bargain with the Foundation itself, by which we mean they submit completely to these scary modern mortals and plead for their lives, which is honestly kind of sad to think about...but at least it doesn't stay sad for them!
br>In the final letters and messages attached to the SCP, it becomes apparent that, years later, this little corner of Hades has become an official Foundation site, its demons enjoying protection as well as cozy jobs, and its damned human prisoners a perfect, replenishable source for human test subjects.

It's all a bit over the top, perhaps, even for the Foundation, but it's a novel idea with an execution that's pretty fun to read.