I've made a build that shows AP Kog'maw power.
Alot of people think thats very stupid , untill they see his power
I like this champion because it shoots from a very long range , and barely dies.
Hope you like it.

I've picked the 9 marks of Greater Mark of Magic Penetration to get extra magic penetration on the mid and late game , so tanks wont dodge all of your attacks.
Also i've picked 9 seals of Greater Seal of Scaling Mana Regeneration to get extra mana regen , it will let you hold a lane for a long time.
Next one is Quints.
3 Quints of AP - So you will get a lil boost at the start. Greater Quintessence of Ability Power
Last one is the glyphs, Greater Glyph of Scaling Cooldown Reduction Extra CDR On the late game - so you can own LIKE A BOSS!

I've picked up those masteries because kogmaw is really squishy and needs some armor , magic ressist and etc.
Also the 4% AP and the 4% Less damage is really helping at the late game.
It may save your life if the matter is 1-3 hp , Last time i've played - ashe left me with 1 hp , because of the tenacity.
Also , you're getting 0.6 ap per level , 15% M.pent , and 3% cdr for kogmaw's abilities.

There was a request for that, and ....... yeah - well.
Okay - the situational items are - firstable - Lichbane , well ... you can get that
but i really wont , because you have your W and when you have insane AP - you can get like 13% or 12% in a hit- but it will grant you movement speed and magic ressist and nice ap, I just dont like that item , because you nearly all the time just shoot from a long range , soo.
you can get lichbane for close battles and magic ressistance , that is okay - it will reduce ur enemy M.R , make sure he has some before you buy that
You can switch the berz greaves for tabi/threads - depends what you need , but greaves are good for the start soo- yeah.

Well , Masteries are made to gain the most AP you can , well as you see - also got mana regen and mana stuff to bomb more and more.
The relic mastery is a wanted because when you hold the blue you want it to stay for more
and when you have baron buff and etc
But you can take spellvamp for a small health gained everytime you nuke someone it can save your life , but yet- i perfer relic mastery.

Pros
You will get lots of kills wherever you lane
You wont die easily
You will catch the chasers
You will own like A ****ING BOSS!

Cons
You will be extra squishy
Mejai wont get lots of stacks
People will try to get fed from you
They will focus you all the time
You wont own :|

I've picked up the long range skill Bio-Arcane Barrage because you need to play very safe at the start and own just at the late game , also you're getting the 6% hp per hit stuff.
After that i've maxed the Caustic Spittle] because you need to reduce the magic ressist , and also get more attack speed for the [[Bio-Arcane Barrage
And i've maxed the slow at the end - because i dont see a diffrence (except for the damage) - The level 1 slow might save your life early game , so dont underistimate it.

Abit Explantion on the skills

[Kog'maws Q] Caustic spittle Caustic Spittle - This is AWESOME because if you shoot it you reduce their m.ressist AND THE PASSIVE GIVES YOU ATTACK SPEED
You should use it really often - it does alot of damage and it has a really low cooldown.
It is really good for creating combos , It does 60/110/160/210/260(+70% Ability power) Magic damage and reduces the magic ressist by 5/10/15/20/25.


[Kog'Maws W] Bio-Arcane Barrage Bio-Arcane Barrage- This is your farming skill - at the early game , when you dont wanna mess with the other champs, you just pick them easily from a distance, and it does 2/3/4/5/6% of their total HP in magic damage every hit
In addition it increases your range by 130/160/190/220/250.


[Kogmaw's E] Void Ooze [Void Ooze]- That skill , is a LIFESAVER , because on the early game , when you're getting ganked , with low hp , you just shoot it back and run for your life , that saved my life for LOTS of time.
That skill does 60/110/160/210/260 (+70% Ability power) Magic damage.
And slows the target by 26/36/44/52/60%, it is really good to slow people and just pick up the kill.


[Kog'maws R] Living Artillery Living Artillery - The Best Skill EVER! :D!
YOUR KILLBILL SKILL , The range on level 6 isnt so long but , its totally worth it - you can take down chasers , check bushes , and the BEST THING - SHOOT FROM A ****ING AWESOME RANGE WITHOUT GETTING HITBACK!
IT DOES 150% EXTRA DAMAGE TO CHAMPIONS! ( It was 250% once but it got nerfed cuz it was too oped)
Anyways thats ur best skill , you can kill everyone cuz that range is the best in game ( except for karthus requiem) but you shouldnt worry bout that. , you're just aiming 1cm behind him and he just runs to it
The Skill does 80/120/160 (+30% Ability Power)(+50% Bonus attack damage - Matters only if you get hextech gunblade)
Dont be afraid - ks your friends when you can just say "sorry" - you need those kills , you need those stacks , whenever you can assist - do it ,its really important.

Last and the best - PASSIVE! -Icathian Suprise Icathian Suprise
That is my favourite passive , whenever you fight someone 1 on 1 and then you leave him like 200 hp and he kills you , you're running at him like a amaniac and exploading on him.

Wherever you are - you should lasthit everyminion you can , 10-15 creeps = a kill.
(at the gold )

Anyways farming is important at the whole game , more creeps = more money
You should use the special skill Bio-Arcane Barrage for that - then there wont be a chance that the enemy champ will hit you , and you will deal extra damage.
You can farm really good when you are using your ULTIMATE on a couple of minions and then the E on them.

I was deciding what to pick Rylai's scepter or Hextech gunblade
You guys may decide whatever you want , I've picked slow, Better no hits then hit nheal
Also there was a decision between Berz greaves and sorcerers shoes.
I've found out that - at the early game you need that 25% attack speed to lasthit easier and etc
At the late game , im selling the berz greaves, and gettin sorcerers shoes - which will give you more penetration.
I suggest you to buy the mejai as soon as possble , but whenever you get money for the tear after the mejai - dont buy shoes first , get the tear - its more important , you will obviously shoot alot which means you will get lots of mana = lots of ap
You should get catalyst right away for extra mana , and then finish it for rod of ages - so you can get the passive faster
If you get lots of stacks late game - Buy rabadon before rilays , if you dont - just rush rilays and then rabadon.

First one is Warwick Warwick OF COURSE! - that guy just heals and heals
well - thats why you have the ignite! , whenever you start attacking this guy
ignite him - he barely will heal then , and that would be easier for you
Second one is Orianna Orianna - Its really annoying to be in the mid lane against orianna because of her long range - til level 6 you gotta play really cautious
but after that , you need to strike her with the artillery few times and then just slow her and smack her off.
Third one is Caitlyn Caitlyn - I - really hate caitlyn , because she is over powered.
But , if you use kogmaw well , caitlyn wont be a prob - she has a short range which means you're gonna pick her really easily if played right.
Fourth one is Brand BRAND - THE ULTIMATE CASTER - Well theres not lot of things to do - just avoid he's stunning hits and etc , if you're doing that , you're gonna own.
Fifth one is Sion Well he's not really frightning but if he's laning , you should really care , cuz he might come and just stun you and then they will all focus you .
Well theres not more to say but :].

Kog'maw doesnt have alot combos - but the combos he has are deadly.
On those chapters i will teach you how to get Kog'maw to the maximum he can.
And if you dont kill with those combos you have your AMAZING BOSS PASSIVE to finish that guy off.
By the way, at level 6 your ulti does alot of damage - like 200-300 to champions (depends how fed you got) , thats the time you should kill them all and get very fed because its doing insane damage at this level to them , they have around 1000 hp and you can kill them very easily.

After doing Q , E , W - You just need to spam your ulti , whenever you can just shot it
it will grant you a victory at the fight you're doing.
and if it wont YOU HAVE YOUR AMAZING PASSIVE!! - Icathian Suprise TO BLOW HIS HEAD OFF!

Damage Output - Excellent

Mana Costs - Depends on how much ultimates you spam , Basicly it is [230] at level 6
And [270] at level 18.

At level 6 - Medium , At level 18 : High - with the ulti spam

The W Is to auto attack between the skills and after.

After doing the organized combo , you just spam your Ultimate again , massive damage.
Again , This is my favourite combo because it reduces the magic ressist and just shred him

Damage Output- Excellent.

Mana Costs - Depends on how much ultimates you spam , Basicly it is [230] at level 6
And [270] at level 18.

At level 6 - Medium , At level 18 - High with the ulti spam

The W Is to auto attack between the skills and after.

Damage Output- OK

At level 6 -Very LOW - At level 18 -Medium

Mana costs - [140] At level 6 , [180] At level 18

This combo is very fast and doesnt make lots of damage , its good to harass.
But if you 1v1 someone , you shouldnt use that combo.

Damage Output- VERY VERY VERY VERY LOW!

At level 6 -Very very very very very very LOW - At level 18 -Very very very very low.

Mana costs - [140] At level 6 , [180] At level 18

This is a fail combo, The whole idea of the combo before that Q reduces their magic ressist and the E makes more damage , That combo is just idiotic.

Damage Output- Ok +

At level 6 - Medium , At level 18 - Medium +

Mana costs [180] At level 6 , [220] At level 18 , If you spam it , it picks up way more mana

This combo is OK , Because you dont have the W that shreds their hp between those skills.
It could have been better

Damage Output- Medium

At Level 6 - OK+ , At level 18 - Medium

Mana Costs [260] at level 6 (If you do it fast if you are doing it slow [180])
At level 18 [280] (Again - if you do it fast if you are doing it slow [240])

This is kinda good because you start with an harras and then just reg combo and finishing it with an ulti again , it makes nice damage.

Damage Output- Bad

Mana costs [110] At level 6 , 18

That combo wont do much damage but it will still make about 30% of the targets health
If you autoattack after it.


Caustic Spittle 64

Damage Output-Good

Its really good to harrass other champs with the magic ressist reduce and then a boom.
Most of the times you will scare him back to his hiding spot.

Mana costs 100 ,at level 6,18

Learn aiming your Living Artillery is a good idea , because it harass and well , you may get lots of safe kills
Everytime you can - Just leave a bomb Living Artillery on your enemies to see where they are and where they're going
Whenever you can use Caustic Spittle on them and then Living Artillery would be an awesome harass , you should use it alot

Q:Why did you pick Cooldown reduction runes?
A:You need your Living Artillery As soon as possible so you can nuke more.
You will get like 24% Cooldown reduction which means that you bomb every 0.7sec which is really awesome.

Q: I don't like Tear of the Goddess.
A: Then don't use it. I'm not here to tell you exactly what items or build to use, it's up to you. The cheat sheet is my personal opinion, and the item section is for items that I think can be considered/should not be used

Q:I dont like mejai soulstealer.
A: Simply - dont use it , its my personal opinion that you can get 180 AP from an item
If played right and i think its the best thing you can buy at the start
but if you dont want it , rush for hextech revolver instead.

If you have another question , comment and ill awnser them.

I really like Kog'Maw even after he got nerfed , he's still goddam op
he got badass ulti and attacks , and if played right - he can penta [Penta pics soon :)]
I like the idea that you can go on a battle of 1v4 and actually win it.

Please , if you have anything to add , just comment and ill awnser rightaway.

Anyways - full credit to Zyv0x, who taught me how to make my guide.