Grenade amumu. 12/0/18, tanking strength of the ages. magic pen reds armor yellows ap blues ap quints
build 
as your core
boots 
or
against ap
against AD
for more damage.
for map control and mixed resistances
this build is insane. you clear fast, deal a lot of damage, and can win fights by yourself. if you want to carry as a jungler i highly recommend trying this out.
oSEXYPLATYPUSo1 votesgrenade amumu is more like 
Marshbouy1 votestoo squishy IMO
oSEXYPLATYPUSo1 voteslol but u will melt 3-4 champs at a time
Slythion1 votesI prefer zhonyas over void/abysall (depends which item I need more) because it gives more survivability, you can cry during the stasis, and cdr for your long ass cd's
oSEXYPLATYPUSo1 votesnothing wrong with that,. but we are talking grenade and a grenade explodes its self and everything around it. its for a lack of better term suicide bomber amumu
Slythion1 voteslol fair enough
I mixed up my traditional AP Amumu with Grenade Amumu