I'm not sure if this is an Easter Egg or Glitch, but possibly both.
I noticed when I bought a house in Riften, I got the Arcane lab, there were two simple, yet "harmless" mannequins. One of my friends reported to me that their mannequins in Honeyside were moving about! Walking, and everything! I decided to check this out, only to see that one of my mannequins were out of place and the other turned around! I got scared, and I haven't entered Honeyside since. If you EVER decide to buy a house in Riften, just beware of this. There's a number of people that say this has happened to them. And sometimes the mannequins will actually kill you and everyone in Riften.