In this version of ghostcraft, Zombies,Pigzombies,spiders,cave spiders and ghasts when neutral are
invisible. (when the ghast shoots it becomes visible)
This version of ghostcraft is harder,better and scarier!
If you downloaded Ghostcraft 1.3.1 then you should get this one.

I can't show you pictures of the mobs because they are invisible.
(exceptions : slime,snowgolem,irongolem,creeper,blaze[unchanged] , magma cube [unchanged] ,silverfish,Enderman and the Enderdragon)