The challenge mode button is the cookie next to the reincarnate button
Challenge Modes are a feature in Cookie Clicker, added in v2.0. Challenge Modes are available only through Ascension, and impose special conditions on a player. As of v.2.002, still only one Challenge Mode yet exists. It allows the player to complete Achievements only unlockable in that mode. You can choose a challenge mode with the cookie button next to the big "Reincarnate" button on the ascension screen. The listed behavior will then be applied to your next run. Ascending again will automatically return the challenge mode to "None".
Challenges
Only one Challenge exists, called Born Again. However, more may be added in the future.
"This kinda defeats the whole purpose, doesn't it?
(Shadow) Indicates Shadow Achievements
Note: All the achievements listed above can also be unlocked on the initial playthrough of the game. However, after ascending once, they must be unlocked through the Born again mode, even if you meet the requirements.
Trivia
In the source code of version 2.0 of cookie clicker, a third challenge mode called 'Trigger finger' has been commented out.File:Arrow special v15.png
The icon it would have in the menu
Its description reads:
"In this run, scrolling your mouse wheel on the cookie counts as clicking it. Some upgrades introduce new clicking behaviors. No clicking achievements may be obtained in this mode.<div class="line"></div>Reaching 1 quadrillion cookies in this mode unlocks a special heavenly upgrade."
It could be a challenge mode that had been planned, but was scrapped for some reason.
Or it could be a teaser for a new challenge mode, which might become available in a future update.
This is likely the case, as there is no other reference to it in the whole source code.
