Heed was hosting a renderman hunt once on bedroom dark. The server had been up for quite a while, and I stayed for a little bit. After a while we started seeing renderman teleporting onto shelves, then watching us for a few seconds then dissapearing again the same way dead player bodies are removed, in that poof of smoke and all.
A little while after that, we started getting freaky chat messages, with riddles and stuff. Then all the sudden I was looking at the shelf for renderman, and I start seeing a renderman loving MOVE and fall down from the shelf, then he starts attacking us. He destroyed builds and killed people when they touched him, and if that's not enough, they started coming in groups of up to 5.
^^^^
I call bullstuff on this being default and normal though, a few of my friends agree it was probably some mod heed added to make them do this stuff, so I don't give it much legitimacy as a true easter egg.