A mob (short for 'mobile' creature), or monster, is an entity that appears in Mine Blocks. There are three types of mobs: passive,aggressive/hostile and neutral.
Aggressive or (hostile) mobs are entities that pursue and harm the player. They spawn in poorly lit or non lighted areas such as night or in underground caverns. These mobs do not spawn in peaceful. Such mobs are:
Mobs that are are not aggressive but harm you when being attacked.