Virus is a microscopic organism that lives in a cell of another living thing. Although viruses are extremely small and simple, they are a major cause of disease. Some viruses infect human beings with such diseases as measles, influenza, and the common cold.
Passive Mobs. Passive mobs are composed of creatures that will never, under any circumstances, attack the player. Some passive mobs can be bred to create more of them, e.g. pigs can be bred to effectively farm them.
Some hostile Minecraft mobs can ride several Mo' Creatures mobs in the same way players can. this includes zombies, zombie pigmen or skeletons riding on horsemobs, wolves and scorpions. When mobs are killed, they drop various items which may be useful to the player for use in many crafting recipes.