so im new to Empire Mincraft, so i went out to the wild to collect mats to build. I started a mine out in a swamp and ran into a cave. While i was mining out the iron a invisible creeper came up to me and exploded. I didnt die from it cause i moved when i heared the hissing, i went back to mine the ore and again another creeper came up and exploded. i dont know if its a memory issue or something else but zombies and skeletons are also invisible but only the bow standing there, but i can see spiders and other non-threatening mobs I.E. cows/sheep etc.EDIT: zombies can be seen and i tryed to quickly log out and log back in when i encountered the invisible mobs but that didnt fix anything.