Pulse Worm is a trinket in The Binding of Isaac.

Causes Isaac's tears to pulsate in size between 1-1.6x as they travel.

The effect affects the hitbox, but not the tears' damage.

Has a chance of being dropped upon defeating Larry Jr., Scolex, The Hollow, or Pin. The chance for a trinket to drop is 1%, with every worm variant having an equal chance of being selected.

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.

The following special synergies and interactions for Pulse Worm 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.

Pulse Worm

• Causes tears to pulse in size
• Golden Trinket (without Mom's Box): Pulse effect doubled
• Mom's Box: Pulse effect doubled
• Mom's Box + Golden Trinket: Pulse effect tripled

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