Hey, I'm not even sure how to describe this. I was caving in my new 1.5.2 server and noticed this large open area where it looked like a block of stone was darker color than the rest. I couldn't see well so I put a torch down and ran back up to look. Then, the block moved. Then there were 2 then 3 of them, moving. Looked like stone. They were clumping together sort of. Then I started taking damage and backed off. I had a wand of lightning but it didn't do anything to it. Then, it retreated into a vertical shaft that went lots deeper, so I capped it with cobble. I have no idea what this was but I wasn't able to fight it like a normal enemy. What did I encounter?