The SCP Foundation is a fictional organisation whose job is to Secure, Contain and Protect (us from), items that break the usual laws of physics. It started on 4chan's /x/ board, some time back in 2007, as a simple post setting out a description of a statue (SCP-173) that only moved when you weren't looking at it, and the precautions that had to be taken to keep it away from people. (Like a lot of SCPs (the short name for these artifacts) it was rather murderous.
As a writing prompt, it was a good one, and /x/ quickly spawned dozens more ideas, of items, people, locations and weirder things, all of which needed to be stopped from going on a rampage. (Or protecting from the many cults that also sprung up around them.) I actually wrote one myself, SCP-113, though as time has gone on, it's been tweaked rather further down the grimdark scale. Check the very first version on the page history for my original contribution (or as near as you'll ever find).
Twelve years later, there's been significantly more effort put into it, with thousands of items and a range of supporting pages, including fiction and general fictional operations manuals that would be associated with an organisation like this. Quite a lot of content to play with, which is why over the years there's been a number of readings or podcasts done about it.
This is about the most recent version though, which does a very good job of combining both the standard format report about each item, and some of the "fanfics" about them. Each episode is read-through of the relevant procedures, but also sneaks in performative elements. These may be dramatic readings of witness statements, or dramatised versions of events that happen around the artifacts. Alternately, there might be interviews with or about the artifacts.
And let's not forget the entertaining experimental logs some devices have, where an amusingly long list of trials get performed, usually with lethal or silly outcomes.
All of this is played over a low bass soundscape, with some impressively ominous noises or disturbing music. It's a clever choice, as the simple reading of the different pages could get fairly repetitive, but with the additional set-dressing around them, they become rather more compelling.
That's also helped along by the selection of SCPs. Given how many there are, it's to be expected that some aren't wildly interesting. Those given a performance thus far have obviously been carefully chosen to be both distinct and have enough lore around them to fill an episode. I'm sure 914 will be along at some point, possibly for an especially long episode, and here's hoping they can avoid some of the more OP self-insert author avatars.
If you've ever read any of the SCPs, this should probably be an automatic listen. If you haven't, give it a try anyway. It's well put together, and is a nice example of adaptation of existing media.
Have a first episode: