Build

Last item depend on the other team, ap heavy = Banshee veil, ad heavy = omens neutral = guardian angel or warmog for lot hp and heavy regen.

Pros:
Good jungler
Strong CC And AOE dmg
Extremely hard to kill lategame

Cons:
Weak lane
Needs blue to jungle fast
depends on his team

Strong and fast jungler. but don't do laneing, you will not get enough farm!

He needs his team to be usefull. Often Amumu gets blamed to be bad, but actually its the team, cause they don't go with him and help him. With the team, Amumu is the strongest jungler in game (my meaninf) due high AOE dmg and CC