Dark Fluoresce

Thank you Sir_Obama. I in fact did have secret rooms mod items in my home. Thanks for the explanation :)

So I was playing Hexxit, and I'm building a house of Marble Stone Bricks. I had the Kitchen and Study and Foyer already done, but I needed to get some Quartz. I went to the Nether, got the quartz, and when I got back, SMACK DAB IN THE MIDDLE OF MY UNDER CONSTRUCTION HOUSE IS A BATTLETOWER! Is this something new or what!? I didn't know that battletowers can generate at random even after the initial world load. This is ridiculous, it took away over half of my house just to spawn the thing! Anyone know about why this happened? I did notice from a distance that a Harbinger was meandering around the battletower when I spotted it. Can Harbingers create dungeons!?