Hello Summoners, my name is Weeznaz and this guide is for people who are new to Kog Maw. Kog Maw is a fun champion who can be played as a either an AP mid lane mage or a Marksman. This introductory guide should help you get started on playing him. Warning though, he is hard top play in either role in Solo que. While his Marksman role is especially hard in Solo Que, his mid lane role is a slight bit easier.

Pros
1: Whether he be AP or AD Kog Maw has excellent late game scaling/ damage.
2: He has long range spells
3: AD Kog Maw is a "tank buster"
4: AP Kog Maw is a poking machine
5: AP Kog Maw has decent waveclear once he has a few items.

Cons:
1: SLOW: His base movement speed is 325.
2: No mobility spells. This combined with a slow movement speed means that if an enemy does get on top of Kog Maw, he can stick to Kog Maw really easily
3: Item dependent: Both AP and AD Kog Maw are useless if they can't get their items as Kog Maw's base values aren't great.
4: Requires good positioning. If you can't position with this champ, you are doomed.
5: Very Little Solo Carry potential: Kog Maw needs to be surrounded by a meat shield team in order to make an impact, unlike other ADC's like Vayne or Graves who can brawl and make plays happen on the map.
6: Low base auto attack range( Only 500 units)

Passive: Ichathian Surprise: This passive turns you into a walking cherry bomb once you die. I describe this passive as a cherry bomb as you only do 125-475 true damage to an enemy depending on your champion level. This passive really sucks: it's not likely for your damage to actually kill the person who killed you. What hurts even more is that while you are alive in combat, you don't have a passive. Definately one of the worst design elements Rito ever came up with. If you do die and trigger this passive, unless the enemy champion is withing lethal range, just try and kill a low minion or 2. IF in a teamfight just put your dead exploding body next to the enemy team to try and get some assists.

Q: Caustic Spittle: This spell has a passive and active component. The active component sends out a small projectile that lowers the enemy's armor and magic resistance. The passive component significantly increases your attack speed. AP Kog Maw doesn't care to much about this spell so he maxes it last. Now AD Kog Maw on the other hand loves attack speed which is why AD Kog Maw maxes this spell second.

W: Bio-Arcane Barrage: This spell gives a substantial buff to your auto attack range and makes your auto attacks deal maximum percent health damage. This spell allows Kog Maw to be an effective tank buster. This spell is AD Kog Maw's bread and butter. He needs this spell to deal consistent auto attack damage since Kog Maw's native auto attack range is low. AD Kog Maw always maxes this spell first. AP Kog Maw also enjoys this spell, and he maxes this spell second because AP Kog Maw utilizes Void Ooze better.

E: Void Ooze: This spell shoots out a long range trail which daamges and slows enemies. The spell has no AD ratios so AD Kog Maw maxes this spell last as it doesn't offer much except for a small amount of peel. AP Kog Maw on the other hand maxes this spell first as this ability scales well with AP.

R: Living Artillery: This spell does what it sounds like: shoots out artillery. This spell is tricky as it starts out having a small mana cost, but as you use it more and more the mana cost increases drastically. AD Marksman needs to watch his mana carefully. I recommend a "1,2 pop" approach. Meaning you use this spell 2 times then let the mana cost reset. Now AP Kog Maw on the other hand get's to build mana which means, he can spam this spell for long periods of time. Not to mention that this spell does double damage to champions, this spell scales very well on it's own. Of course as AP and AD Kog Maw you take points in this spell at levels 6,11,16

Summary:
AD Kog Maw: R>W>Q>E
AP Kog Maw: R>E>W>A

As both AP and AD Kog Maw your playstyle is that of a cannon: You stand as far back as possible and pump out as much damage as possible. If you get too close to the fight, pretty much any champion can stick to you and kill you. As AD Kog Maw you want to work around your Bio-Arcane Barrage cooldown, meaning when it is up you attack but when it is off cooldown you are very vulnerable so stay back for a few seconds til the W comes back up.
As AP Kog Maw you have 1 job: Make it rain artillery. Since AP Kog maw builds mana, you can afford to spam your R like crazy and simply poke out your enemies. As Ap Kog Maw you don't want to be in range to auto attack, be just in range to R them.

As AP Kog Maw your 1 job is to make is rain artillery shots and not get caught. The first step to solving this problem is to build up a mana pool as Living Artillery gets very expensive.

Item 1 in all situations= Tear of the Goddess: You need to buy this item early so you can build up a strong mana pool.

Item 2: Now you might be thinking "Why not complete the Tear into Seraph's Embrace immediately?" Well, you absolutely need to start stacking tear, and you ABSOLUTELY need to purchase the item that can help you reposition and help you deal with your low movespeed. You muse purchase the Luden's Tempest. This item gives you the much loved 10% increased move speed, a respectable amount of AP, and the flat damage proc gives you a nice power spike when combined with the range increase on your ult at level 11. I always rush this item after Tear of the Goddess

Item 3: Sorcerer's Shoes. Still stressing that repositioning and mobility thing that will keep you alive.

Important Note: CDR items have little Benefit for Kog Maw. This is because the cooldowns on all of your basic abilities are so high and the cooldown on your ult is so low that purchasing CDR doesn't really do you any good. If you are familiar with Corki's kit and cooldowns, Kog Maw goes through something similar to this.
So the following items Ionian Boots, Nashor's Tooth, and Morellonomicon, are not good on AP Kog Maw

Athene's Unholy Grail: This is the only CDR item that might be good on Kog Maw. You would buy this item to ensure that in the late game you can regen enough mana to continuously keep spewing your ult. I haven't tried this out yet, but in theory should be a good late game item to help you keep spamming spells. In theory, I wouldn't buy the whole thing until late game, but I might buy Chalice of Harmony after my Luden's Tempest and Boots.

Item 4-6: At this point in the game you look to see what you situationally need.

Zhonya's Hourglass if you are against a team that has 1 person who can easily get to you [Rengar, Vi, etc]], then I would consider this item. If you are against an all AD team I would consider this as item 4 or 5. If this is not the case, you can post pone this to be your item 5 or 6 if you even feel that you need it.

Void Staff: This is what I typically purchase as item 4 simply because it's a cheap and effective powerspike for your ultimate which already has decent damage.

Liandry's Torment: I love this item as it makes me slightly more tanky and survive longer in fights, as well it helps deal good poke damage to enemy tanks. This item combined with your ultimate can over time widdle them into nothing.

Rabadon's Deathcap: This may sound weird, but you don't need to rush this item. You ultimate doesn't have "fantastic" AP ratios in the early game. In the early game due to your lower mana pool, and because AP Kog maw has a weak laning phase, I usually prefer to go for the cheaper powerspikes that come from magic penetration items. I usually make this my item 5 or 6, but if you are snowballing and having no problems just pick up this item and poke the game to death.

Banshee's Veil: IF you are against a high AP damage team and need to survive, this item is a good one to consider to pick up in the late game.

Quicksilver Sash: If the enemy team has a disable that WILL kill you [Zed's Deathmark, Fizz's Shark, etc] you should really look into this item. This thing has saved my life. Downside is it doesn't build into an AP item, however the active can be so good and crucial don't let that downside impact your decision

Guardian Angel: It's a long *** game and you absolutely can't afford to let the enemy remove you from the fight. This item can be great in that respect. Just know, this item is great when the enemy team has 1 big threat. If they have multiple threats I would go for a health based item.

AD Kog Maw plays differently than AP Kog Maw, as he must auto attack the target to do well. Please do so only when W is off cooldown or if you have no other choice.

Item 1: Always Trinity Force: Why this item first all the time? Well this item gives you a ton of movespeed which you need and the Phage component helps you kite out dangerous situations. Additionally, Kog Maw makes really effective use of Sheen procs. Also gives Kog Maw, a weak champion, an artificial powerspike.

Item 2: Always Blade of the Ruin King: This item has fantastic tank busting potential, this item combined with Bio-Arcane Barrage will eat alive even the beefiest tank. Additionally, this item is separated into cheap components and has a reasonable price. An important note: use the active DEFENSIFELY. If you use this active offensively, you are WAY TO CLOSE! If the enemy gets close to you then use the BORK active to reposition.

Item 3: Tier 2 Boots. Gotta go fast

Item 4-6: These items are based on situationa

Infinity Edge: If you are dominating your game and the enemy team doesn't have a strong tankline, just pick up this item and end the game. The infinity Edge combined with sheen procs makes for a very strong trade.

Last Whisper: This item is almost a necessity in your games. If the enemy tankline starts to build armor, pick up this item.

Mercurial Schimitar: If the enemy has a form of CC or damage that will really mess you up, the "clease" from this item can save your life.

See the other survival items I talk about in the AP Kog Maw section

Most of the rune page for AP and AD are standard, but there are a few points I wanted to touch on.

Move Speed Quints on AD Kog Maw: In my opinion, Kog Maw doesn't really benefit a whole lot from the early AD Quints, and he gains a very small benefit from Attack Speed Quints. Move Speed quints on the other hand really help you in the early game avoid and dodge bad situations. Also in my opinion, since you build/earn enough attack speed and do a ton of damage that what you need more importantly is kitability. I like this on AD Kog Maw, but I haven't had success with it on AP Kog Maw just because going into mid lane with low AP in the early game makes your already rough laning phase even rougher if you can't secure minions with your E.

Scaling Health Quints on AP Kog Maw: Scaling Cooldown Glyphs on Kog Maw are a waste, Scaling AP glyphs are acceptable but not great, flat AP do a decent job of helping you secure mininos during the hard part in the beginning but don't offer much long term benefit. In my opinion Magic Resist or Health are the way to go in terms of glyphs, I just prefer health as this stat is a universal defense stat.

both the AD and AP mastery pages are simply standard Marksman and Mage pages. Since Kog Maw does a lot of spell weaving and doesn't rely on crit damage I don't take the mastery that buffs you when you get a crit.