HERO INTRODUCTION
--The Alchemist is a difficult foe to handle, but if left to his own devices he can amass enormous amounts of gold at an alarming rate. His Acid Spray covers a large area with toxic chemicals, which deal physical damage and reduce the armor of any foe caught in the cloud. Attempting to fight the Alchemist while in an acid cloud is foolhardy at best, especially if he uses his Chemical Rage transformation skill. Chemical Rage drastically increases the life, regeneration, and attack speed of the Alchemist, transforming him into a deadly fighter. Possibly his most dangerous skill, however, is Unstable Concoction. Although it takes some time to charge, Unstable Concoction results in one of the longest stuns in the game and causes a good deal of damage. Although the Alchemist can be annoying to fight, it's best to keep a close eye on him. Goblin's Greed directly increases the amount of gold the Alchemist gains when killing creeps, and as he kills more the bonus increases. Unless kept in check, this Goblin/Ogre combo can cause a lot of mayhem late in the game.

BACKGROUND STORY
--Having enlisted under the ranks of the Sentinel for mere personal gain, the Alchemist's quest for amassing wealth to fund his research is a tireless and relentless one. Both sadistic and cruel in his methods, this heartless Goblin cares not what means he must resort to for a sizable bounty. Whether he chooses to paralyze his foes with toxic concoctions or drench them in corrosive acids, Razzil Darkbrew remains steadfast in his calm, calculated approach, despite their constant wails of agony.


Skill build:
Level 1: Unstable Concoction (Shake)
Level 2: Acid Spray
Level 3: Shake
Level 4: Acid Spray
Level 5: Shake
Level 6: Chemical Rage
Level 7: Shake
Level 8: Acid Spray
Level 9: Acid Spray
Level 10: Goblin's Greed
Level 11: Chemical Rage
Level 12: Attribute Bonus (Stats) / Greed
Level 13-15: Stats/Greed
Level 16: Chemical Rage
Level 17-25: Stats/Greed


-- Shake should always maxed first. It's what makes Chubby good outside of Rage as a great utility skill.
--Acid is taken alongside this. During midgame, the effects (both the DoT and armor reduction) are at peak effectiveness. It also ensures you can defend a creep-push with ease.
--One level of Greed is taken after Shake/Acid are maxed at level 10. This allows a succession of lasthits or fast-track jungling to give a sizable gold boost.
--Rage is taken anytime available, for obvious reasons.
--The remainder of Greed's levels are optional, as taking stats will help shore up your greatest weakness. And at this time, pushes are so huge you can easily reach the Greed bonus gold cap. Personally, I would take 5 stat-levels before putting 1 more point in Greed (+100% effectiveness) and then return to max-out stats.


Items Build:
Starting:
--Alch starts off with various choices on what to take to his lane. This will mostly depend on your team's structure; if you're playing babysitter to someone else (as you should be IMO), then a Basilus should be your first purchase. Supportive Chubbies should get either a Magic Wand's components or buy a courier off the bat. If for some reason you are going solo, bits of Bracers will maximise your lifespan in-lane.
Babysitter's Basilus:  


--Basilus offers all Chubby needs earlygame: a slight damage boost, badly needed armor and a source of light mana regen to continually use Shake. If you're taking a dual-lane (as you should), your teammate will adore you for the auras as well!
Later on, you may consider breaking apart your Basilus so as to use the Sobi Mask for an Urn (see core item build later).
Self-Sturdiness: 


--To boost your already good starting stats even higher, grab the classic Bracer set-up of 2 gauntlets and a circlet. This will increase your already sizable hitpoints to very safe levels, and boost your manapool enough to sparingly use Shake until level 6. Best in a solo lane, if you really are shoehorned into one.
Stick Magicry: 


--A Magic Stick can also work wonders. You sacrifice some personal stats for the Energy Charge skill, which is definitely more useful earlygame; early attempts to fight back against your Shake will be mostly nukes or disables, so if you can survive them (easy thanks to your great starting HP), a buildup of charges can be very tide-turning indeed. In this kit you also take along the 3 GG branches needed to later turn it into Magic Wand, which can replace a Bracer's space and more than make up for a minor loss of Strength.
PETA will sue: or


--Your earlygame is quite good thanks to Alch's good base stats and Shake's lane-staying power, so if your team requires a Courier it may be your first purchase as well. Here I take along a Ring of Protection to help reduce harassment and build into a Basilus later, but if you wish you may want to buy a Flying Courier straight away. In either case couriers have a slight personal risk; not doing well in-lane because you lack the benefits of other items might gimp your earlygame. However controlling a lane and farming quickly can get you those missing bonuses via Courier, thus granting you those crucial items just that bit faster.
Consumables: or

--I've never found the need to use Clarities, ever. Your Shake is very manacost-efficient, and if used sparingly will not demolish your manapool. Likewise, you won't be spamming Acid.
Health-wise it's a tossup between Tangos and Salves, but personally I prefer Tangos just for the ability of staying close to the action. Especially important if your lanemate's in a messy situation!
Optional: SOMEONE WILL GET THE AXE: 

--I have bad experiences with Quelling Blade. When it first came out, I loved it so much that I bought it for every single melee hero I played, including our lovable Chubby. Then when it was pointed out all it really did was increase the last-hit error margin, I tried to wean off it.
Needless to say, this was not fun.
But if you need it, get it. Alch's attack damage will love you for it, but midgame Acid and having good last-hitting skills shake their head in disapproval.


Core:
Heart of Chubby: 
Ogre-Slave Shoes: or
Can of Whoopass: 
Optional Boosters:


--Contrary to popular belief/misconception, Alch does not need too many items if used optimally. Armlet of Mordiggan and mid-tier footwear are easily affordable by midgame, even if you allowed your lanemate free farm over the enemy creepwaves. These aim to emphasize Chubby's sizable DPS ability midgame, thanks to Acid and Shake being at top potential and Rage a quite scary improvement to his damaging carry-capability.


Post-Core


--What you get now is highly dependant upon what your team lacks; Chubby is one of the few heroes who benefits from virtually any item. In this guide, I prioritize remaining a threat to the enemy by buying items that focuses attention on you.
Here are some suggestions of item builds to fit the role you need to play:


DPS/Carry
Start with: oror
Followed by: or
Optional Supplement: 
--In order to play Chubby as an effective carry/tank hybrid, you must maintain the high threat level required to keep the enemy team focusing upon you in Rage. Therefore our major DPS booster will be one with a powerful and obvious secondary effect; Radiance for the DoT around yourself, Mjolnir for the Chain Lightning of rape and Deso for the physical damage amplification. Since your EHP remains naturally high until lategame, I would recommend aiming for Rad; if there is a better carrier in your team, go for Mjol or Deso.


Utility/Support
Start with: 
Followed by:  
Crowning Touch: 
Optional: 
--This build makes use of Chubby's ability to use spells more freely than others, thanks to Rage's massive regeneration. While giving up your battle skills, a good supportive Alch can prove a great damper to the enemy just as well, provided with a coordinated team!
Bear in mind while Khadgar's Pipe is optional, the item itself is most useful during midgame where a stray AoE spell can prove devastating to the unprepared team! So if you wish to get a Pipe, you should do so sometime around your acquiring a Necronomicon before its benefits are less effective.


Mates and Hates:
(AKA Friends and Foes)


Awesome Allies
Seriously, who doesn't synergise with Chubby? Carries love him for his babysitter mastery and gay disable, nukers love him since he makes their job simpler, disablers love him as he can use that borrowed time to wail away... the list goes on.
Here's a list of specifically deadlier combos:

etc...
Anyone dependant on landing hard-to-aim spells will love your Shake for setting up their own combos. With these heroes, ask them to wait until after your stun to use their skills.