This works very well for me, cept I take tele and flash, but other wise, great build :)

If you ever get in ranged or stunned you are dead look into Banshee's veil/Wit's end also Kogmaw does a lot of spamming abilities and autoattacks so i would think lichbane would be a great item on him. So item build with survivability would look something like this. Sorcerer's Shoes, Wit's End, Deathcap, Lichbane, Rod of Ages, Rylia's scepter and if you are having trouble with AD champs owning your face get a Thornmail instead of rylia's and proceed to give them the middle finger.

no vote yet

PotatisFarfar : Rylais is a must on Kog'Maw. You NEED to get it before rabadon, since it gives you health, lots of ap and a powerful passive. the slow WILL make sure you NEVER miss your ulti (and you want that :p) I tried getting a rabadon before rylais, and trust me, rylais IS A LOT better :) Plus, you want the 500hp. Glass canons are useless lol. Of you like to make glass canons (glass canons = lots of damage output, but no survivability at all, like health, armor or magic resist), remeber this : While dead, you do NO damage :)
As for the abyssal, I don't know why i picked it instead of void staff, seriosuly XD Thank you for showing me this dumb mistake ^^
I also prefer getting exaust instead of ghost, but that is a personal preference.
I used to upgrade archangel right away, until i discovered how expensive it was, for not much AP. I upgrade it as my last item now.
I'll have to try this famous hybrid Kog'Maw. I never saw one, but i heard it was pretty good :p
As for the runes, flat AP is only good for the first 10 minutes lol, while magic penetration is good for the whole game. Again, this is also a personal preference, since I also have a full armor penentration book, and a full magic penetration book ^^ I really love to see my enemies wonder how i can do so much damage even trought they get magic resist/armor :D Thank you for your comment

I preefer hybrid kog ;) but still, some feedback:

Runes: Flap ap quints is better.

Mana regen/lvl is better.

Flash/ghost combo is better. Ignite works to.

Rylais is kinda bad, not worth rushing, rather rush rabadons.

Abyssal is a waste, you shuld never get in range of the enemies for it to be worth it any way... Wuld change the core to void.

Uppgradeing archangel right away is a waste, wait to do it after your rabadons.

Like this. Rod ---> Rabadons ---> Staff

That is all.

nastors couldnt hurt...

Shadow QQ - I will test that as soon as i can. Thanks for the advice.

Kloney - Thank you

Buried Alive - AS kogmaw is awesome because of bio-arcane barrage, and its even strong if this skill is combined with mardred's bloodrazor's passive. Have you ever tried an AP Kog'Maw? It's really fun to play, since the enemy team just dont no what to do XD
They can't tower hug, they can't run away, they have no choice, but to rush like noobs in ur team for a fight, because u r alwasy ''poking'' them with ur ult ( wich kind of hurt) But honestly, it really depends on your preference and on your team's champion selection. If you have 3 AP champ, 1 tank, logic tell you to go for AS Kog'Maw.

I would like to know why you prefer ap kog maw to AS kog maw but then again mit is just my personal opinion to play AS kog maw xD if you do well on AP kog maw then go for it but i still prefer AS :P

Awesome looking build i dont usually play kog maw but i got a great score with this :D keep it up!

+1 for AP , try to change seals to mp5/lvl