Ultimate Challenge Challenge

Description
Complete other challenges (without the normal rewards).

Despite being listed in the "Reset GP" section, this challenge does not reset your GP purchases -- nor does it even trigger a Rebirth. During this challenge you can freely start other challenges as you normally would, with all the normal requirements and restrictions for each. However, you will not get the normal rewards for completing them. Instead, the Statistics Multiplier reward counts toward the completion of the UCC. The UCC is complete when sufficient Statistics Multiplier has been gained from other challenges. The goal begins at 2 million (2e6) Statistics Multi for the first UCC, and increases by that amount for each one you complete -- 4 million for the second, 6 million for the third, etc.

Completing a challenge for the first time in a UCC awards the normal amount of Statistics Multi, but each repetition of the same challenge awards 20% less (additive) until the end of the UCC. Therefore, there's no benefit to completing any challenge more than five times in one UCC (with the 5th only giving 20% of the normal Multi).

While in a UCC, the tooltip displayed when hovering over the Challenges button on the Rebirth tab will show the challenges you've completed in this UCC, the Statistics Multi needed to complete it, and the amount earned so far.

Unlock Condition
Maximize the following challenges: UUC, PMC, NDC, 1KC, GSC, AAC, CPC, DRC, and CBC.

Restrictions
You will not receive normal credit beyond the stat multi reward for completing other challenges. during UCC.

Recommended Stats
None.

Reward
Challenge Points: 45 Statistics Multi: 1.0 million

You will receive the equivalent rewards for 3 other challenges up to a maximum of 10 each in the following order: UUC, PMC, NDC, 1KC, DRC, and CBC.

This means if you finish 5 UCC you will receive challenge credits: you will receive 10 additional planet levels (10x UUC) and +10% energy from UB’s (5x PMC) Completing all original 20 UCC will reward you with an additional 5 completion rewards for your GSC, AAC, and CPC. Completing all 20 UCC also raises the cap for completions of NRC by 5 and PBC by 25, but does not provide the rewards. If you had previously capped the rewards for one or both of those challenges, the bonus Challenge Points you received for capping them will be rescinded (possibly resulting in a negative Challenge Point balance) until you reach the new cap for those challenges.

After UCC 20, the rewards change. For UCC 21 and more you get a retroactively multiplier for overflow points. It starts at 1% per UCC from 21 to 30, increases by 1% per UCC for every 10 more. Capped at 7% per UCC. So for example having done 51 UCCs would mean 64% bonus. They also increase the cap of the points you can get from OCs by twice as much. Currently the cap is 500, so with 51 UCCs the new cap would be 1140. Completing #30, #40, and #50 also provide new OP purchases. Starting from UCC 55, every 5 UCCs you do will add 1 level to each OC purchase without cost increase (if a OC purchase has a cap like V2 Auto Kill, it can't go over the cap).

Here is a summary list of the completion rewards for completing an individual UCC

Strategy
For post-20 lategame UCCs, TLC (1.5M), SDC (1.75M), and V4C (3M) can be worth it as long as they can be completed in under 3 hours. The Compiled Spreadsheets contains a UCC challenge calculator.