Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
I wrote this build because I've recently started playing around with Urgot. I think he can be pretty amazing and a hell of a win in a team fight. His ult doesn't do much except make him beefier and makes him switch places with the enemy selected. Now the problem with most Urgot's is they use this in the middle of a team fight and place themselves in a position where it's insta-death. We're going to try and avoid that in this guide.
Acid Hunter: This is your main damage dealer with this build. It is a skill shot attack that is based off of your attack damage. It can only hit one enemy at a time, so use it wisely. Note: If you hit the enemy with Noxian Corrosive Charge (E), it is no longer a skill shot and will hit a target affected with Noxian Corrosive Charge (E).
Terror Capacitor (W): While this can be an amazing shield if you spec for ability power, this build does not focus on it. It will absorb damage based on the level of the skill, but more importantly while shielded your auto-attack now has a slow affect. I see a lot of Urgot's go in and use this first to try and tank, but I find it's better to pop it later in the team fight to mimick Ashe's frost arrow and get a few more kills since you should be able to out-damage the opposing team.
Noxian Corrosive Charge (E): This is your primary harassing tool and that is why you level this first. It has a great range and splash or AoE target. It is not your nuke type spell in this build, but simply a harassing and last-hit tool. It can help you farm tremendously and get the last-hit on minions for the gold you'll need. Note: If you hit the enemy with Noxian Corrosive Charge (E), your Acid Hunter (Q) will auto-lock on any target affected with Noxian Corrosive Charge (E).
Hyper-Kinetic Position Reverse (R): Your ultimate does two beneficial things for you. First, you will switch places with the target and stuns the target for one second. It also grants you added Armor and Magic Resist for 5 seconds. Based on this build, you will be hard to kill once you've ult'd. HOWEVER this does not mean switch spots with four of the enemies ready to nuke you in a team fight.
Early-game: Defense, defense, defense. Pick your Acid Hunter shots wisely and don't be afraid to harass with your Noxian Corrosive Charge. Work on farming as much gold as possible for your build and only attack the enemy champion(s) when you're sure you can fire your Acid Hunter successfully. Burning through your mana will all but disable this champion. However, if you're smart about it, you will be able to manage your mana efficiently enough without a Mana Regen item. Once you hit level 4-5 you should be able to get your first kill if you've harassed effectively. If not, when you hit level 6 hit your shield, ult them into the tower, hit them once with auto-attack and then hit them with Noxian Corrosive Charge and finish them off with your auto-attack or Acid Hunter. (Really shouldn't take this much to kill one champion at this level, but hell get the job done.)
Mid-game: Hopefully you've gotten your boots and your BF sword by now. If it's a slow game with kills then focus on farming. There's no reason with your damage-over-time that you shouldn't be getting all of the golden goodness. Go jungle for blue buff inbetween kills as spamming Acid hunter will make you g-g-godlike. The cooldown reduction and mana regen can be all the difference for the ganks you will be basking in. If they start to run, ult the squishiest champion back into your team and start running towards the champion and finish him or her off. At this point, you should be ready for Black Cleaver and Malady (I took for survivability. They can't kill me, but they get me low enough to where I either need some healing or to go back to base).
Late Game: This is the most fun part with Urgot in my opinion. By now it is likely you are getting focused on every fight and your Noxian Corrosive Charge probably isn't doing much unless they've completely ignored magic resistance. Either way, it's time to build your Hextech Gunblade and start using it more often. Minion waves will fall quickly between your auto-attack and your Noxian Corrosive Charge. You should be able to handle the turrets efficiently at this point and continue to gank the opposing team pushing back. After this, I just stack Sunfire's because my ultimate makes me unkillable even with their armor penetration, and if they are that close they are taking huge damage from me.
Scenario: 320 + 55 = 375 magic damage fron Noxious Corrosive Charge (E) + 80 magic damage from Sunfire Cape (x2) per second + 250 + 277 = 527 damage from Acid Hunter which you can spam constantly, all while having a slow auto-attack when your Shield is up. Total DPS approximately 700-800.
All in all, this is my first build. If you don't like it or have suggestions, please let me know.