Mob is invisible when spawned with a egg or a command

I was checking out the new snapshot, when it was the time I spawned a panda, I can't see it. I thought it was just my computer being a little slow. I waited, still, no sign of a panda, so I spawned the beast, when I spawn it I heard its hard breath but still no sign of the beast, I hope you can tell me whats wrong with my Minecraft or if its a bug.