Wost spam I've ever seen? I was the creator of the worst I've seen!
I'm not gonna reveal how I did it, but I was able to make the bricks so that they're completely decollisioned. I go on some server hosting The Slopes, make a tower of 64x64 flats on an area they're building in, and TA-DA! A tower of decollisioned bricks consumes their builds. Did I also mention that you can walk through the tower? And that when you do, it lags like hell? It's true!
EDIT: I forgot to mention that they cannot be destroyed. Even if you clear my bricks, they'll still be there. The host is forced to restart the server.