Daemon's Tail is an unlockable trinket in The Binding of Isaac.

Replaces 80% of hearts from room clear rewards with keys.

Decreases chances for heart drops from all sources, and increases chances for other rewards to be selected instead.

For example, it will decrease heart drop chances from Blue Fire Places, as the heart drops can be replaced with nothing.

All heart drops turn into Black Hearts whenever possible.

This page shows the latest information as of the new Repentance+ (Online Co-op) DLC.
To see information about this trinket for the previous Repentance version, check this page instead.

Defeat Satan as Azazel.

Daemon's Tail can be found in the following item pools:

The following special synergies and interactions for Daemon's Tail have been documented.

* Note that not all possible synergies and interactions are listed here.

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.

Daemon's Tail

• 80% of dropped hearts are replaced with keys
• All heart drops become black hearts
• Golden Trinket (without Mom's Box): Blue and purple fires drop black hearts instead of soul hearts
• Mom's Box: Blue and purple fires drop black hearts instead of soul hearts
• Mom's Box + Golden Trinket: Blue and purple fires drop black hearts instead of soul hearts

• Check out the trinket description on the external Isaac Wiki.