This is my first build here. I came up with this build while i was trolling in a game,and tried it out. It actually worked, so i thought that some may find it interesting.

The skill sequence is quite simple here: you just raise the vorpal strikes and after that the feral scream, which has good damage even without ability power.

The masteries are 21-9-0. Since it is an attack damage build i put 21 points in offense and 9 in defense, to be a little tanky.

The runes depend clearly on you but i give a good example of runes for this build. 4 critical strike marks and 5 armor penetration can help a lot. Cho gath's early damage is quite low, so some armor penetration and critical chance can help a lot. Also critical is important until late game. As for the seals, i use health regeneration, which work well with Cho'Gath' s passive(each time you kill a minion you regenerate health and mana). If u get damaged, at early game, you can just play defensively until you have fully regenerated and can go on the offense again. The glyphs are critical chance again. Yo will need as much critical chance as possible when playing this build, since u don' t get critical from the items. The quints are attack speed because Cho' Gath' s attack is quite slow.

Firstly, i start with a tear of the goddess. It gives you some good mana and mana regeneration. Then I take the boots, and make the tear of the goddess to a manamune, which is quite cheap and can give quite a lot of attack damage. After that, i buy the warmog' s armor which,with Feast, gives a huge increase of maximum health. Then, with all that health, atma' s impaler will just greatly increase your attack damage and also gives armor and critical chance. The last two items, which you' ll probably won' t be able to buy in every game since they may not last so much, are frozen mallet, which further increases your damage and wit' s end, to have some more attack speed and magic resist. Also, wit' s end passive works quite well with vorpal spikes, increasing your damage a lot. Also, nashor' s tooth or hextech gunblade work equally well.

Flash is important in this build. Like with all champions, you use it either to escape from enemies, or chase them, to secure a kill. Exhaust can really help. Cho' Gath isn' t very fast, so exhausting the enemy, will help you catch them and finish them off.

Generally, it may seem like a troll-build, but it actually is good. You can just make any personal changes you want or even play pure ad(infinity edge, bloodthirster, phantom dancer etc.). I suggest it to anyone who wants to try something different.