Build Guide by Tacosaurus-R3x
Not Updated For Current Season
This guide has not yet been updated for the current season. Please keep this in mind while reading. You can see the most recently updated guides on the browse guides page.
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.
So, as far as posting builds go, this will be the first one I've ever done. I take pride in thinking a little outside the initial view of any champion. If I fell like a build is too popular, I won't use it. I'm a hipster like that. :P
Well, this is possibly the second most successful build I've ever made, the first now being an obsolete relic with the constant patches. So without further adieu, let me explain my thinking with this build.
Some of you may be thinking that this type of a rune page is silly. "Straight attack speed would never work!" You scoff. Well, it does, for one particular reason. *points at malady and black cleaver* They work on number of hits you land, the faster you hit, the more stacks they get, the better damage you do, the more your teammates can do. So yes, straight attack speed does help a lot. That's really the only reason to have such a high attack speed bonus right from the get go, that and the fact that you main magic damage comes from the combination of madred's bloodrazor and bio-arcane barrage, both of which are magic damage on hit.
As you can see, I go 16-0-14. The 16 in the offensive tree goes down to get both types of penetration masteries as well as the bonus attack speed and cd reduction. I get the archmage's savvy over deadliness because there is a sad lack of pure ap items in this build, so every bit helps. The exhaust mastery also helps if you get conered by a single person or someone is getting away, so the extra armor/mr reduction and .5 second duration increase help a lot. In utility I go for the reduced death timer because it helps a lot later game and I am by no means the perfect, un-killable kog'maw. The ghost mastery is also picked up as well as the increased exp in case you wind up roaming or denied farm by the enemy team. The extra mana from expanded mind helps keep you in lane longer early game if you tend to run out of mana easily. Greed is picked up for obvious gold-producing reasons. Then put the last two points into quickness for a bit extra movement speed.
I get ghost and exhaust together because they make for a great chase/escape combo. That's really it, picking up both of their masteries since they are early on in their respective trees make them that much more valuable. That's really all I can tell as to why I pick those masteries. It's really up to you, though my common back up if I feel like something different is heal/ignite.
Here I get to explain to you my thinking here. As I mentioned, madred's bloodrazor and bio-arcane barrage are the main magic damage dealers in your arsenal, and they both are on-hit effects. So malady is usually my first item to pick up, it helps both with physical damage and magic damage with it's combination of attack speed and magic resist shred per hit. Don't forget to get your boots after this or before you complete malady depending on how often you find yourself having to recall from close brushes with death because you aren't fast enough. I usually get boots of swiftness, though you'll want to get merc treads if they have a lot of crowd control on their team. What comes next depends on the enemy team really. If they have a lot of hp heavy characters or it seems they love stacking armor instead of magic resist, get madred's to significantly increase your damage output. If they start stacking magic resist and start ignoring armor or if they don't really have much hp to begin with, you can pick up a frozen mallet for some damage/hp/chasing power. OR, since it is cheaper, you can pick up black cleaver. Cleaver is in there for the same function of malady, just for the attack damage side rather than the ability power. That's really where the build branches out into different forms. Depending on what you just got, be it madred's frozen mallet or black cleaver, could determine what you get next. If they continue the path of magic resist or avoiding hp items, then you will probably want to get the one you didn't get between black cleaver/frozen mallet. If they start stacking hp you might want to wait for the other one there and get madred's bloodrazor to add some more magic damage. It all depends entirely upon the enmy team, the only thing that is consistent after malady and boots is that hextech gunblade is always dead last. I know it sounds weird to make it last, but it's just icing on the cake, the last little birthday candle if you will, it is not mandatory for your damage.
Now the theory behind all of this. Kog'maw is a heavy auto-attacking champion, especially in this build. What I aim to do with this is to exploit the combination of physical damage and magic damage being dealt at the same time. By the time you finish just malady and black cleaver, every time you auto attack you deal physical damage, shred magic resist, shred armor, and with bio-arcane activated you deal magic damage as well. All in one hit. When you finish the build you are guaranteed that magic damage with every hit from madred's and your bio-arcane should tack on another seven percent for a scary 11% of their max hp per hit in additional magic damage. And if they stack magic resist to lessen the damage from that deadly combo, you have malady to shred through up to 24 magic resist, which is around 15% reduction gone and you have the additional 10% from the archaic knowledge mastery. If they stack armor to stop the physical damage portion you have black cleaver to rip through 45 armor and Sunder to go through another 3 points which is taking away almost 50% damage reduction from them. And if they split up their resources between armor and magic resist, it's better for you because it means neither will get high enough to be a serious hindrance after you are done shredding it all. And to top it all off you should have max, or close to max, attack speed at the end of this build, which means you can complete the stacks for malady and black cleaver both within two seconds.
Now doesn't this sound like fun?
Another good thing about this build is with frozen mallet you slow with every hit, so unless they cleanse+flash away, they're probably never getting away. You also have the slow and ignite-like effect from hextech gunblade once you complete the build. You can also provide good support in team fights as a great tank buster, mainly because of your shred and multiple damage type with a single action. So if they have a heavy CC type tank or off-tank, say swain or alistar, you actually can reduce their effectiveness as a tank and make them a viable target in team fights. Do not forget that malady and black cleaver benefit your entire team, so spread the love if you can. :3
I don't really have anything unique to say here as to why I get these spells the way I do. I just like to max bio-arcane first for magic damage pre-madred's with my second focus being caustic spittle for it's additional armor shred and bonus attack speed. Void Ooze and Living artillery fall behind as tools to prevent escapes/chases or scouting, though it is a good thing to get every level of living artillery as soon as possible.
So in order of importance from most to least:
Bio-arcane Barrage -> Caustic Spittle -> Living Artillery -> Void Ooze.
I probably just prattled on and typed your eyes out without really getting my point accross sadly. So here's the TL;DR:
Runes provide you with great attack speed to maximize the stacking effects of black cleaver and malady while also allowing you to hit quite often with two types of damage in one action. Masteries give you some added bonuses, mainly in the form of some extra shred in the offensive tree and extra movement speed and exp from utility. As far as summoner spells go, I feel ghost and exhaust together form the most capable combination for both chasing and escaping. As far as the items go you have black cleaver and malady for shredding of both magic resist and armor while madred's grants you some addition ad and magic damage per hit and frozen mallet slows enemies with every hit while granting a nice ad/hp boost. Boots of swiftness help a lot for chasing and escaping and Hextech Gunblade offers both ad and ap with life steal, spell vamp and an active effect similar to a mini-ignite with more slow. Focus on getting bio-arcane barrage first in skills, then caustic spittle while getting living artillery at every chance possible with void ooze really only getting one point at level 1 for nothing more than assistance in chasing or escaping until it's the only skill that you can get.
That's really all I can give you, the rest is explained in the different sections. If you have questions/comments/feedback just rate and don't ferget to leave a comment as to why you gave it the score you did.
Kthnxbai from the dinosaur made of mexican food.