A mob, short for 'mobile' creature, is a type of entity with a proper AI that allows it walk/jump/fly. There are three types of mobs: passive, aggressive/hostile, and neutral. Mobs may be hunted for mob drops, used as decoration, or kept as a pet, although the only one that can be properly tamed is the wolf.
Passive mobs are entities that do not harm the player, even if attacked. These mobs spawn in peaceful. Such mobs are:
Aggressive or hostile mobs (or monsters) are mobs that pursue and harm the player. These mobs do not spawn in peaceful. Here is a list of them, divided up according to where they spawn.
These spawn in the Nether:
These spawn in the end:
The flaming chicken spawn when a chicken is set on fire:
Undead mobs (the skeleton and zombie) will burn during the day time, eventually dying if they do not find either cover underneath blocks or water.
The enderman does not burn during the day, however, it usually teleports away, eventually despawning when it gets too far away from the player.
The flaming chicken can be made into a normal passive chicken by pouring water on it.
Mobs that are are not aggressive but harm you when being attacked. These include:
The wolf, when attacked by the player, will follow them around, doing damage. It is an overworld mob.
When a zombie pigman is attacked by the player, others will be alerted. This means they will all chase the player in order to inflict damage, and will not stop until the player dies or leaves the nether. They only spawn in the nether.
When a cactus cow is attacked, it will run at the player and deal damage.