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Mystery Sack item
Mystery Sack is an unlockable familiar in The Binding of Isaac.
Description
Spawns a familiar that follows Isaac and drops a heart, coin, bomb or key every 5 or 6 rooms alternatingly.
Pickups can be of any variant.
Note
This page shows the latest information as of the new Repentance+ (Online Co-op) DLC.
To see information about this item for the previous Repentance version, check this page instead.
How to unlock?
Defeat The Lamb as Eden.
Item pools
Mystery Sack can be found in the following item pools:
| Name | Weight |
|---|---|
| Treasure Room |
1.0/1.0
|
| Secret Room |
1.0/1.0
|
| Beggar |
1.0/1.0
|
| Greed Treasure Room |
1.0/1.0
|
| Greed Secret Room |
1.0/1.0
|
Tags
The following tags are applied to this item:
| Id | Description |
|---|---|
| summonable | Can be summoned via  Lemegeton. |
| offensive | Can appear for  Tainted Lost. |
Special synergies
The following special synergies and interactions for Mystery Sack have been documented.
| Mod | Item | Synergy |
|---|---|---|
| --- | BFFS! | The familiar drops pickups every 4 or 5 rooms. |
* Note that not all possible synergies and interactions are listed here.
Internal item description
Below is the Internal Item Description as shown in-game.
Note that some stat changes are not displayed here. Please see the main description for the full effects.
Mystery Sack
• Familiar that drops a random pickup every 5-6 rooms
• Abyss: x1 locust 1x Isaac's damage
External links
- Check out the item description on the external Isaac Wiki.
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Headless Baby 
Leech 
BBF 
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Best Bud