Wrap. Cry. Temper-Tantrum. Wrap. An enemy has been slain! Amumu is a super-yordle! Most tanks aren't good for much except for defending in the Crystal Scar. They don't output enough damage to make a mark there. That is not true with Amumu. Amumu is a great offensive champion as well as defensive. Follow this build to become a very powerful yet sad mummy.

You guys might doubt me, but look here:Same game, the amount of magic damage I had dealt:
The second game only lasted 9:47 because we dominated them so hardcore:

Armor and Magic resistance is a priority. You need to be pretty close to your target for most of your damage to take effect. Also a little bit of magic penetration will make all the difference with Despair and Sunfire Aegis. Grab two Greater Quintessence of Movement Speed to keep up with your opponents.

Defense is awesome. It means your enemies can't hurt you while you do continuous damage to them. I grab utility because I like to be in the fight as long as I can for more points. Grab what I have indicated above. You can go to offensive masteries if you grab cooldown reduction and magic penetration if you prefer to deal maximum damage and not stay in the fight as long.

What is best to get:

Ghost: This summoner spell is almost necessary in Dominion. You need to be able to rush to and from Capture Points. (NOTE: Don't forget to change your masteries if you don't get Ghost!)
Flash: I take this spell whenever possible. That short distance will save your life so many times and allow you to get kills.

What not to get:

Revive: This spell is the worst summoner spell ever invented. Never get it. Death time really isn't that bad in Dominion unless you are always dead.
Promote: I don't really see a point in getting this summoner spell. This is what I think about it: "That big-*** minion you just created? It is going to die really soon, and you probably won't even capture the point."
Clarity: No need for this spell most of the time. About the only time I'm out of mana is at the very first. With the increased mana regeneration from Crystal Scar buff, it comes back relatively fast.

Items

1. Start with Blasting Wand and Boots. The AP from the wand and the speed will allow you to travel and hit really hard.
2. Next in line is Negatron Cloak followed by Abyssal Mask.
3. Sorcerer's Shoes is next. You are going to want that magic penetration for this build to work.
4. Grab Sunfire Aegis next. Start the recipe with Giant's Belt.
5. Get Thornmail after Sunfire Cape. These two items plus Abyssal Scepter will give you pretty much all the defense you need.
6. Get Rabadon's Deathcap for high AP. You will be amazed at how hard you will start railing them with Bandage Toss.
7. After Rabadon's Deathcap and if you have time still, get Zhonya's Hourglass You will be smashing their faces in so hard that they will become the sad ones when they see you.

Tips and Useful Knowledge:

• Abyssal Mask's magic resistance reduction makes Despair and Sunfire Aegis's Area of Effect damage go up. Instead of 25 damage from Sunfire Cape, it will do more like 34 (depending if they get magic resist).
• When ambushing a champion, try to stay where they can't see you but Bandage Toss can hit them. Aim where they are going to be in a small moment. Late game, this will be really annoying to them especially when you run away and then do it again.
• I would usually go Mercury Treads as Amumu, and I used to when I first started using him. Trust me, Sorcerer's Shoes are much better.
• Start by going mid. As soon as you capture the point, check up top. If they need help, go top. if they don't need your help, then go to the other side and capture their mid.