Mobs in Nether

In Overworld there were a lot of mobs some dont attack some attack.In Nether all mobs attack.In Nether  is so dark theres everywhere  fire and lava ....

Zombie Pigman: Zombie Pigman appears in the Nether or when a pig is hit by lightning(in Overworld).When he get attacked,it will summon all nearby Zombie Pigmen to attack.They drop Coocked Porkchops andGold Nuggets.

Ghast:Ghasts fly around Nether.THey shoot Fireballs wich can be deflected by shooting them with an arrow.They drop Gunpowder and Ghast Tear.

Magma Cube:Magma Cubes are fire slimes found  in Nether.They drop Magma Cream.

Blaze:Blaze light on fire and then launch three fireballs at the player.They fly too.They drop Blaze Rod.

Wither Skeleton:Wither Skeletons spawn in Nether Fortresses and drop the heads needed to summon the Wither.They drop Coal,Bones,Wither Skeleton Head.

Wither:The Wither is the seccond boss mob added to the game.it is summoned by placing Wither Skeleton Heads and Soul Sand into the pattern bellow.The Wither will attack any creatures in range.
                                                                       WWW
                                                                        S S S
                                                                           S

Beware from them they take a lot  of damage.