Hi there, i´m going to make a guide about how to jungle with AP amumu.
This is my first guide so i would be glad to get some critics how u think about this guide.

So why Ap amumu and not tanky? Tanky amumu does quite well, espacially in teamfights, but i missed the fun and the possibility to nuke enemys on my own, so i tried to create a usefull AP build. And believe me, it´s definitly working during the whole game.
And it´s funny as hell!

Pros :
+Massive Nuke, easy to play
+does very well in jungle after the first few levels
+can easily decide a teamfight
+extremely funny to play

Cons :
-relatively squishy
-hard to jungle at the first few levels

I take full AP runes to get the most possible AP boost at lvl 1. This will help you till you get your first AP item.

For masterys i take 21/0/9. As tank amumu i usualy took 9/21/0 wich made jungling very smooth for me. With 21/0/9 jungling you will be much more vulnerable to creeps at the first 3-4 levels, but then it will work pretty well.

I start off with a
Regrowth-pendant and a Heal Pot. After i worked my way through the jungle and finished golems, i port back an finish Philisopher´s Stone and get some more Heal Potions. Then i keep going till i got enought money for Will of the Ancients, at least for Hextech Revolver. The Spellvamp will give u enough Health Regen to stay in the jungle as lang as you want. After Will of the Ancients i finish my boots and buy a Giant´s Belt. From Now on you should be able to do really well in every situation and after a few kills and somemore jungling you can build up a lot of AP.

I start with Despair, it´s your main jungling spell and should be maxed first. Of course Curse of the Sad mumie should be taken when possible. Get your Bandage Toss at level 4 so u can gank from far away positions, 1 point is enought till lvl 14.

Use Smite and Flash, this gives you the chance to jungle and counter jungle pretty. Furthermore Flash is always a good choice for offensive and defensive actions.

Start at Blue, ask for a pull from your teammates. Then continue with wolves, wraiths and then golems. Port back, buy Philisopher´s Stone and some Health Pots and then go back to wolves, then wraiths again. Get your red buff and from here on you should be able to gank quite well. Always look for a chance to steal the enemys blue or red, this will slow down their jungling.

I hope you´ll have fun tryin out my guide and give me some tips how i can improve it.