[Phylum]

I was exploring a large cave system earlier when I was confronted by 2 creepers and a zombie. I managed to fight them off, proceeded down dark, windy corridors and killed 2 more creepers when I reached a fork. I went right, but I soon hit a wall. I then went back and killed 2 creepers that had appeared at the fork. I then started down the other path and was confronted by a creeper. As soon as I killed it, 2 more came down and attacked me. I killed them and took a few steps before I was confronted by yet another now dead creeper. I'm too terrified to continue down that path, so I've just blocked it off.

If I didn't know any better I'd say that there's a creeper spawner down there.