"It all started with SCP-173. It was a random, one-off creepypasta, but it inspired a lot of people. before long, other entries started popping up, and then one day someone made a wiki for it, so they wouldn't all 404 eventually. This was when /x/ was still young-ish, and The Holders, Ted the Caver, Treedog, and other old-school /x/ rubbish was still very new and decent. -DrGears" - wiki
Source: http://scp-wiki.wikidot.com/history-of-the-universe-part-one

So, from these comments I'm getting that it started out as the wiki? It would sort of make more sense that way ( By the way, for the people who are confused about my comment below, I posted that when the OP referred to S.C.P as a ceepypasta).

SCP = Scary Crap Pants

It's about time we're getting some attention.

SCP means Special Containment Procedures. It says so on the wiki's FAQ.

What does SCP stand for? "Special Containment Procedures". We generally go with "the Foundation". It also stands for the site motto: "Secure. Contain. Protect."
Source: http://www.scp-wiki.net/faq

S.C.P. also stands for Secure Contain Protect also..

Spyder not at all. The SCP Foundation has roots (the first few things about it) in creepypasta, but quickly became a standalone thing, and the game came out afterwards, featuring only a very small amount of SCP objects and entities.

scp stands for Special Containment Procedure

You could've used original S.C.P. logo ...

it started out as a wiki over five years ago, then the game and as such is not a creepy pasta as it is standalone thing.

well the S.C.P foundation Series I cases and the histories are my favourites

S.C.P is a creepypasta? I always thought it started out as the game, then the wiki, not that it started as a creepypasta!

norm