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Mystery Sack

AchievementRebirthUnlock unknown

Achievement details

Achievement number: 124
Description: Unlocked a new item.
Requirement: Defeat The Lamb as Eden

How do you unlock Mystery Sack?

In The Binding of Isaac, Mystery Sack is unlocked by earning the The Lamb completion mark as Eden (Character).

Structured pathSource-backed requirements are mapped into trackable steps.

Unlocked a new item.

Eden (Character) → The Lamb (normal)
1. Defeat Satan 5 times to unlock The Negative. source
2. The Negative is a guaranteed drop from Mom; take it, then defeat Satan in Sheol and touch the chest to enter Dark Room. source
3. Find and defeat The Lamb in Dark Room. source
- Eden (Character)
  - Eden (Achievement)
    How to unlock: Complete Chapter 4

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What unlocking Mystery Sack leads to

Source: bindingofisaacrebirth.wiki.gg

Imported 2026-09-13