XXXXXXXXL is an unlockable challenge in The Binding of Isaac, added in the Afterbirth DLC.
This page shows information as of the latest Repentance release.
To see latest up-to date information about this challenge for the new Repentance+ (Online Co-op) DLC, check this page instead.
There are no starting items defined for this challenge.
Note: this list does not include characters' default starting items.
Every floor is the size of the Womb if it was affected by Curse of the Labyrinth!. However, the floors of each chapter are not combined.
The following is unlocked for completing the XXXXXXXXL challenge: Gold Heart
Defeat Mom for the first time.