Okay well, this guide will be different than others, and it should be, most guides are more or less the same, and one always gets voted highest and people seem to ONLY build that one champion by that guide, well, this is why im making this one, it's all about options, and i believe AP Kog'Maw is extremely better than AD/AS.

This guide isn't meant to be flashy, to be appealing, it's just to give you some details and knowledge about how to play kog'maw and how my build is mostly successful, i rarely have a negative k/d/a ratio.

kay well for runes, I go for maximizing your damage, with Magic pen quints and mark, and ability power glyphs and seals, your damage will kick *** starting level 6, You can go for ability power p/level, they work too, but your early game wont be strong at all and you'll have to play extremely defensive, as everyone knows how squishy kog'maw is anyway.

HP Quints are also viable, i use them on occasion when i solo que.

Standard caster 9/0/21, we're going for offensive in this build and boosting our summoner spells for extra defensive early-mid game.

Right at the start you want a mana crystal and a potion or two., you're going to rush arch staff/boots depending on how well you do at start, Kog'Maw is possibly the worst last hitter in the game, his animation is slow and sucks compared to champs like Ezreal, but do try your best. Since we're maximizing our end game potential as Kog'Maw we need flat AP, hence why no defensive items, you shouldn't be focused much in team-fights, ill explain this later in the guide.
End game, you'll have amazing penetration against squishys, theyll have minus resistance against you, and even tanks will be cut in half with your epic penetration.

Most AP guides say leave caustic spittle till end game levels, well why this may be okay for taking down tanky champs mid game, this is not your priority, as anyone can grab a mandreds and take down a tank, this is not our goal. Caustic spittle does EXACTLY as much damage as void ooze, in 1v1s this will help greatly, early game you want to sit very close to your enemies, so that you can spam caustic spittle, your ult will always hit, and void ooze is just as good as caustic and is also great for farming creep waves, Don't forget about your passive, there's no cooldown on it, so even if they just about kill you in a fight, unless they're master yi or nidalee, you'll get the kill anyway, even if its a bad tradeoff. It may cause your lane to push more.

Flash and ghost are pretty self explanatory, ghost can help you get that bit of range to finish of a running champ with your super long range ult, and flash to get out of those sticky situations, never use flash offensively, ever, it's your panic button!

This build is great in my opinion, i have helped dominate many team fights as Kog, AD is great too, but it's too easy and boring, auto attack? sure, you may be able to dish out 4000 damage on tanks in seconds, but apart from that you get nuked down, and that leads to buying defensive items, where all your damage goes down the drain, this lets you output ridiculous damage to supports and ranged carries while still being able to take down tanks, remember, his arcane barrage scales with AP.. free mandreds.

Team fights are were Kog'maw really, really shines, his ult range at level 11+16 is incredible, meaning you can contribute to teamfights with extreme damage output while staying out of range of all the anti carries, meaning if someone wants to kill you, they have to get through 4 other people ;)

Your caustic spittle, while short range, can help take down champs who have that extra bit of armor, meaning your entire team does bonus damage to them from lack of armor.

Bio arcane barrage, at max rank and with around 400 ap, will do twice what mandreds does, while you wont have the highest attack speed in the game compared to AS/AD Kog'Maw, this will help considerably against tanks, which is where your AP damaging spells suffer at.

In team fights you generally want the enemy team to come to YOUR tower, so you can tower hug and nip in with ghost, firing off as many missiles as you can, don't worry about your mana, your items should keep you topped up, and if not simply grab golem.

As i was saying, use all your spells to focus down the squisheys like sona and anivia who attempt at staying out of range, they won't be expecting to get hit so hard by your barrages, and trust me, anyone without bonus magic resist, will be hurt, with your Void ooze and one barrage, it will estimate rougly at about 900 damage, with 400 AP, then you have caustic spittle for another 500 damage, and your ult is spammable, so yes, your damage is practically unlimited.

To finish up, farming, at rank 5 void ooze you can oneshot the mage creeps, and combined with your ult, twoshot the other creeps. your a great farmer end game, but until then, just try to last hit, he's extremely mana hungry.

Pros
Extremely viable in team fights mid-end game.
High damage output.
Fun to play.
Feared of by anyone.
Hard to get to.
You're a freaking insect.
Can scout brushes for ambushes.

Cons
Extremely squishy
Quite tricky/vunerable skill shots.
Needs practice to use ult well.
Requires slight amount of feeding to do well. Should be no problem.

Thanks for reading, i know im not the best writer in the world, but this build works for me and it should work for you too, i have fun as kog which i don't with most champs, please offer me constructive criticism and help me improve, i might learn something too :)

You don't have to comment to vote, but it'd be great if you would.

Thanks, Womackx, see you ingame :)