Ultimate Arty Challenge

Description
Like a UBC, but you lose even more and can only press the rebirth button 4 times.

Unlock Condition
Complete one UBC.

Restrictions
On top of everything you lose in a UBC, you also lose your training cap reduction, planet, and access to TBS. You will get 4 rebirths to get to Baal (5 if you include the rebirth to initiate the challenge, rebirth number is in parenthesis on the rebirth button).

Challenge rewards that are disabled: GPC, UUC, MMC, TMC, UBV2C (Autokill only), NDMC, DRC, MQC (Divinity bonus only), NDC (Div Gen size and creation cost bonuses only), CBC, DBC, DUC, DMC, and DNDC (creation count bonus only).

Challenge rewards that still work: AAC, BHC, UPC, CPC, PMC, 1KBHC, UBV2C (Multiplier increase only), OC, GSC, MQC (Demon Lord and regen bonus only), NDC (Div Gen worker bonus only), 1KC, OCCC, NRC, PBC, NRDC, UBC, PGC, UCC, DPC, and DNDC (creation cost bonus only). Note that some of these rewards aren't relevant for a UAC.

Recommended Stats
While there is marginal benefit from a few other aspects of the game in a UAC, it is good to have a basic knowledge of most of the game mechanics, as well as being fairly well read on various strategies.

Reward
200 GP, 10 million statistics multi, and 2% P. Baal growth reduction additive with UBC reward to a max of 50%. Refer to the UBC section for details on how growth reduction works. Completing the UAC for the first time unlocks the turtle pet, and a pet token is awarded for the 2nd completion. The 3rd and future completions earn you a Class Change Token.

All of your GP stats will return after completing this challenge, and like the UBC, any GP spent during the challenge is refunded.

Finally, you get a neat, cosmetic "arty was here" sign.

Strategy
The benefits from NRC, 1KC and AAC help with this challenge. This challenge is probably best saved as one of the last challenges you should do, because it takes several weeks even in endgame and can take several months early on. The rewards for a UAC are also not proportionate to the effort. As an early challenge it will unlock training caps that would have to be unlocked anyways, while as a later challenge, you will have completed more of the associated challenges such as NRC, 1KC and AAC’s.

One of the best pieces of advice floating around is to use your first three GP to buy 1k clones as this effectively doubles the speed of your first rebirth. All other GP should be spent on Build Speed. the most important rebirth is the first one and it is highly recommended looking at a guide before and during your first rebirth, as the rest of the rebirths are simply a matter of standard but slow play.

TL;DR first rebirth: focus on training skills first as those unlock the auto training for all of your physical and skills trainings. Don't rebirth until you have the clone soft cap. Don't forget to use potions!

There are a lot of strategy guides on Kong and steam forums, but mostly it's just a matter of waiting, the most important this is knowing which gods to get to before rebirthing. Without hitting these targets, you will have very little chance of completing the challenge. Here is a very short table outlining approximate numbers to aim for.