The way of trolling your opponents,

well nothing much to say but some of the items are situational and varies upon enemies.
teemo probably gunna counter you hard unless u nom nom nom him first lol.
this is still not fully tested but still a fun build, trust me ;D.
do try this out on ur games but don't blame your team mates for losing and or dw when they blame you for losing lol.

Pros:
- you are a freaking teemo
- super fast attack speed
- probably gunna make someone in the game laugh at
your build but you can probably destroy them in seconds
- nice to see a big chogath with lighting fast attacks

Cons:
- pretty darn squishy without frozen mallet
- teemo and anti meele can kick your *** pretty easily

Well for your summoner i'd suggest the following:
Ghost and exhaust

- ghost is to chase your opponent and close the gap for your attacks and ultimate
- exhaust is to slow the enemy you are chasing

Other summoner spells

Flash
- and escape tool and a gap closer, though it was nerfed, still quite effective
Cleanse
- removal of CC such as stun slow dot and ignite, useful when being cc and also an effect tool for escaping
Heal
- pretty darn useful for chogath since it can bait and save team mates, also it can prolong your fights so you can spam dat true dmg ult
Ignite
- just a finisher not really important, though its useful against high recovery and life steal champs, chogath has tha ulti that can finish no prob
Teleport
- solo top lane and good for ganking
Smite
- a jungle chogath is as scary as a jungle rammus
Revive
- lololol bd chogath or insta res
Clarity
- not an ap cho not really needed
Clairvoyance
- uhhhh take it if you want to be annoying but it can save ur life and not waste money for wards
Surge
- lol bigger cho ftw, but pretty useless, BUT do use it in dominion with shield buff LOL you are super mega size with full stacks of your ult
Promote
- mega pusher skills and good nexus killing tools but has tha cool down =(

Laning

get rupture first
max your vorpal spike first
feral scream can be left for last though you can alternate between this or rupture

Jungling

get vorpal spike first and max out immediately obviously
rupture then vorpal

Ult is a must (well duh) 6,11,16

When fighting
get tha squishes and tha dmg, all we need to know for tha team fights pretty basic

Well from the topic you already know what this build is

IT'S ******** TEEMO MAN~!!!

lol but seriously teemo build works on chogath o.O

vorpal spikes with = lololololdmg

frozen mallet is there to slow and for health but the atmas is not really needed you can always change it for a guardian angel

boots varies on the situation
boot of swiftness is great for closing the gap but gives no benefits except the movement speed

CC = Mercury's Treads
AD = Ninja Tabi (good early game but should exchange it for something else)
MOAR ATTACK SPEED = Berserker lol
for the more lol and troll = exchange malady for ionic spark XDDD

Well people would say that ad chogath is probably better than this build
well kinda =(, though the massive attack speeds from bloodrazor malady and wit's end, ad chogath crit hurts Q.Q

BUT TOO BAD THIS IS A TROLL BUILD NOT INTENDED TO BE A PROPER BUILD D=

Lots of runes choices

atk speed glyph and armor pen mark gives a great start on jungling and early games
all in atk speed is just LOL
quint is really up to you really
moar atk speed = better ;D

Not really 100% tested but seems pretty viable lol