Meconium is an unlockable trinket in The Binding of Isaac, added in the Afterbirth+ DLC.

Adds a 33% chance for any poop to turn into Black Poop.

Adds a 5% chance for Black Poops to drop a Black Heart when destroyed.

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 Ultra Greedier as ???.

The following special synergies and interactions for Meconium 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.

Meconium

• 33% chance for poops to be replaced with black poops
• Destroyed black poops have a 5% chance to spawn a black heart
• Golden Trinket (without Mom's Box): 66% chance for poops to be replaced with black poops
• Golden Trinket (without Mom's Box): Destroyed black poops have a 7% chance to spawn a black heart
• Mom's Box: 66% chance for poops to be replaced with black poops
• Mom's Box: Destroyed black poops have a 7% chance to spawn a black heart
• Mom's Box + Golden Trinket: 100% chance for poops to be replaced with black poops
• Mom's Box + Golden Trinket: Destroyed black poops have a 10% chance to spawn a black heart

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