I am out of FAQs to give.
SCP-914 is undoubtedly one of the most infamous articles on the wiki, and due to its nature, there are lots of things you could do with it, which is why we have an extensive experiment log dedicated just to shoving shit through 914. Because of this nature, people ask loads of questions about it. Seriously, if I had a nickel every time somebody asked “What happens if we put SCP-682 through SCP-914?”, I’d actually be able to afford to go to college, and I live in America. But for those that don’t have the time or reading comprehension to get through almost two thousand (at the time of writing this) individual tests, or have read the experiment logs and are still confused, I’ve composed this page of Frequently Asked Questions regarding 914.
Disclaimer: I'm not an actual authority on how SCP-914 functions. I'm just a writer who's been working in the experiment logs for a while, and I made sure to do extra research while compiling this document, so I'd like to think I know my stuff, but ultimately I'm not the one who's responsible for deciding the rules.
"Where did 914 come from?"
No definitive answer. There is a tale written by Gears himself detailing a possible "origin story" for 914 which you can read here, but Gears himself states that this is in no way meant to be canon.
"How does 914 work?"
It's a mystery, and it's best that it stays that way.
"Is 914 sentient?"
Out-of-universe, we are aware that 914 isn't actually sentient, so there is no point in trying to argue that. In-universe, on the other hand, it is still highly disputed and perhaps will continue to be indefinitely.
"Why doesn't the Foundation just put all their armor and weapons through 914 on Very Fine to give themselves super equipment?"
Because 914 doesn't actually work like that. It is not keen on just directly improving all of its inputs with no drawbacks whatsoever. Rather, it is a snarky little shit, and its idea of "refining" things usually just means making them more complex or abstract without necessarily improving them. This, combined with how unpredictable 914 can be, means that it is prone to producing outputs that might do us more harm than good, so testing already dangerous objects with 914 is highly discouraged.
"Why doesn't the Foundation destroy dangerous SCPs by putting them through 914 on Rough?"
Several reasons come to mind immediately. Some SCPs such as 682 or 096 would be too dangerous to transport to 914's location. We also don't know for sure that 914 would destroy them. There's a test in the experiment logs where somebody attempted to put an anomalous mug cat through 914 on Rough at least fifty times and it didn't even put a dent in him, so it's evident that destruction is not guaranteed through the Rough setting. It is simply too risky.
“What happens if we put 682 through 914 on Very Fine?”
This was explored in the tale It Had All Been For Nothing. Obviously, this is a joke, but if I’m being honest here I don’t really think this question is worth pondering. The obvious answer is that you'll most likely get a creature that is even more unstoppable and will likely wind up destroying all of humanity, and we can probably just leave it at that.
"What happens if we put 999 through 914 on Very Fine?!"
The closest we've come to answering this one is a very very early test (0196, specifically) in which amounts of 999's slime (not 999 itself) are put through 914, which you can read here.
"WHAT HAPPENS IF WE PUT [insert literally any SCP here] THROUGH 914?!?!?!”
Please, stop. Most likely there is literally no way to answer this question because SCP-914 is an unpredictable and cheeky little shit and there are possibly infinite choices as to what it might do to any input, SCP or otherwise. Since it is now forbidden to test SCPs with 914 without O5 approval, it is unlikely that your question will ever be answered definitively in the logs, so please leave it to your speculation and let the rest of us focus on more important matters.
"What happens if we put food through 914?"
Most food isn't allowed through 914 because biological testing is banned, and most food is biological. The exception is made if the food is processed enough that it barely even counts anymore, like cake or Twinkies.
"Wait, what counts as biological testing?"
Biological testing bans you from testing with organisms (dead or alive), including microscopic ones. Generally, if it's a life form made of cells, it probably won't pass. The exception would be materials like wood, leather, or coal, since these are far removed enough from their original biological properties that they do not pose nearly as much of a risk anymore. Like with testing SCPs, you can technically test biological matter if you get approval from O5, but you must have an extremely good reason for doing so, and your test will be held to a much, much higher standard of quality. For this reason, it's not a good idea to attempt a biological test until you're very experienced with writing 914.
"What happens if we put [literally anything else] through 914?"
Chances are, somebody has already tried it in the 914 experiment logs.
In the case that it has not been tried in the experiment logs: If that object is not an SCP, not biological, not an explosive, and otherwise just not a stupid idea to test with, I highly recommend that you actually try to come up with an answer to your own question, write a test about it, and submit it to the 914 sandbox. The answers to "What happens if we put so-and-so through 914?" don't pop out of nowhere, the writers come up with them and make them happen. Once you stop asking other people to give you the answer and realize that you can just come up with something yourself, the sky becomes the limit.
"Hold on a second, I saw a test in the experiment log that tests with SCPs/biological matter/dangerous weapons! Why were those allowed?"
The experiment log used to have a much lower degree of quality control in the past, so many older tests break the rules that we have set in place today.
"Where is 914 located?"
SCP-914 is contained in Site-19 Facility 23. Now, don't let the site name fool you. Facility 19-23 is an entirely separate building from the main Site-19, and it is implied to be far away. It is a relatively small facility; while lots of anomalous objects outputted by 914 are stored here, and there are also unexplained locations in the vicinity, 914 is the only actual SCP at this site.