Deadly beings that are always looking for life to consume can take control over the animals. Nearly all of them are sleeping inside cows brain, but every painful stimulus can cause them to awaken. When you attack cows without using any weapon, this monster can appear. Possessed cows can wander across the world even during the day. If they attack you, day can be changed into night. Also if you don't use weapons, every one of your attack may cause them to change day into night.
Drop Sunlight Drops Rarely, which can be used to make it daytime. Drop Cow Spawn Eggs Often.