*Disclaimer - I was running this server so there were no mods installed that could have possibly done what I am about to recount. I'd used all server mods before and after this and never saw this happen nor has it ever happened since. This is not a joke and it actually happened to a group of us playing MineCraft one night.*
It all started when a group of us from G4P were all playing on our MC server. We had just started a new map and were starting to build up our settlement. It was getting to be night so we placed a few torches outside around the ground to keep the monsters from spawning all up on us while we were trying to build.
I was building inside of my wooden structure when I noticed there were a few extra torches on the walls than what I remembered placing, and I am usually pretty anal when it comes to placing torches very symmetrically.
I walked outside to see who was placing torches in my house when I noticed that there were quite a few more torches outside too... and they were placed in a very grid-like way. I started asking questions over Ventrilo and that's when we started to notice that the torches were actually duplicating and expanding their influence... much like the creep in StarCraft.
here are some Screen Shots (since I know if there are none.. then it didn't happen):
This was taken from where we were building.
This one was me running out until the end of the spawned area.
More from inside the town.
As far as you can see almost.
Ground Zero: Towards the end... as you can see there is a torch in every single available space...
Cartographer #1
Cartographer #2 - 20 minutes after #1
And finally.. here is a video:
It was late and we were all pretty tired... so excuse the over-excitedness and occasional swearing.
http://youtu.be/IT3MB-MZBbY