There's a short story about how all the secrecy surrounding the containment of 231 is nothing but a gigantic ruse cruise by the Foundation to prevent the cult from finding out that the Foundation successfully delivered the baby, who turned out to be [url=http://www.scp-wiki.net/scp-999]999[/url], whom they plan to use against his father once he grows up. 

My favorite is [url=http://www.scp-wiki.net/scp-1802]1802[/url], a tiny golem made of garbage that collects and contains anything he doesn't understand, which is everything, made by a group of artists to parody the Foundation. They don't get the joke and in the end are tricked into containing a perfectly ordinary bottlecap just like the little trash guy does. The real magic, though, comes from the discussion page because in a glorious example of life imitating art the people on the site [i]also did not get it[/i] until someone made the joke clear. 

Other good ones are [url=http://www.scp-wiki.net/scp-2521]●●|●●●●●|●●|●[/url], an SCP that contains no writing, and [url=http://www.scp-wiki.net/scp-1594]1594[/url], which I think is just about the most Junji Ito article on the entire site.