Forum:Bullshit

For some reason when a catch a wild horse it wont let me keep it. I was riding a regular horse when I saw a zombie horse running by. So I caught it. I rode it for a little bit then dismounted to kill a couple of zombies. When I whistled for the horse it did not come. The regular horse I had before came. It has done this to me multiple times. Does anyone know whats going on?