This build is mostly used for 3v3, although it can be used for 5v5 as well. If you use this build, you are almost always at least get at least a double kill. Generally, when I use it, I get about 2 double kills, and sometimes triple kills.

For masteries, you want to focus almost completely on attack, although its also really good to help the ghost spell, as well as magic resistance, because that is most likely the only way you'll die.

The items MUST be bought this in this order. I found that when I skipped Berserker's Greavers, I was to slow, and if I was ever ganked, my chanced of survival was almost zero. Phantom Dancer also helps with speed, which will be needed even more later, especially when your damage is high and you can do hit-and-run tactics on the whole team, which I will explain later.

Flash and Ghost are REALLY help full for escape, which you will be doing a LOT of with this build. In a 3v3 game, you can get away with hit-and-run tactics unlike 5v5. If you see all of their Champions together in one game, about to destroy a tower (or just walking toward one) this is EXTREMELY helpful. You can do BATTLE CRY first, then AUDACIOUS CHARGE, as well as THREE TALON STRIKE. If your damage is high enough this should be enough to kill someone like Ashe or Tristana. If not, then do CRESCENT SWEEP, the ult. The character should now be dead, and your health around half. Do flash, and get out of the fight. If needed Ghost can be added, but this rarely happens.
Your biggest danger for hit-and-run is Karthus. At level 18, his AP can be INSANE, and after he dies, he continues to deal damage, if other Champions are present, this is fatal. The only way to beat it, FLASH, the second he dies, get the heck out of there, the ghost if needed, you should Barely survive. But survive none the less.

Pros
-You generally began to get fed with this build, and began to pull ahead of the rest.
-After you're fed, double kills and triple kills are almost easy
-Minions die in 1, sometime 2 hits, and gold come extraordinarily fast
-Generally you can KS really well if you want to.
-It take several Champions at once to kill you.
-This build give you a great Kill/Death Spread
Cons
-You get very few, if any assists.
-This build is difficult in a 5v5 game, mostly because hit and run is harder.

This build is insanely difficult to beat when two characters fight 1 on 1 in in the Twisted Treeline. Eventually, when you've done LOTS of hit-and-run kills with out dying, you will start to advance levels faster, double kills will become common, triple kills will happen. I have gotten 36-3-3 on Twisted Treeline with this build, and I plan on getting even better than that.