If it was a mantis shrimp, there is a possibility it would kill everything else. I doubt it is though. Pistol or crab would be my guess. I used to hear that clicking for years and never saw anything hurt. I was in there with a flashlight in the middle of the night for what seemed like months, and never found a thing.
If you got your rock from Florida, I would think mantis, but Indo, I would think otherwise.