Backstabber is a passive item in The Binding of Isaac, added in the Afterbirth+ DLC.

Tears deal double damage and inflict a bleeding effect when they hit enemies on the back.

Affected enemies bleed for 5 seconds, taking damage at a rate that scales with their movement speed. The faster an enemy is moving, the faster it will take damage. These enemies will also leave behind red creep that damages other enemies for 2 ticks per second at a rapid rate.

An enemy's "back" is considered the opposite of the direction they last moved in.

Enemies that are standing still don't receive the extra damage.

The amount of damage dealt per tick is equal to 2.8 + 0.3 × CurrentFloor.

The effects of Backstabber can also be inflicted by shooting familiars.

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.

Backstabber can be found in the following item pools:

The following tags are applied to this item:

The following special synergies and interactions for Backstabber 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.

Backstabber

• Striking an enemy from behind deals double damage and applies a bleed effect, dealing additional damage over time based on its movement speed and leaving a trail of creep
• Abyss: x1 bleeding locust 1.5x Isaac's damage

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