Backstabber

Backstabber is a passive item added in The Binding of Isaac: Afterbirth †.

Effects

 * When tears land on the "back" of enemies, they deal double damage and inflict bleeding.
 * Bleeding enemies take damage equal to 10% of their maximum health every 5 seconds.
 * Bosses cannot be inflicted with bleeding, but will still take the extra damage.
 * The extra damage is dealt even if the enemy is already bleeding.

Synergies

 * Shooting familiars: Tears fired by familiars can inflict the effects of Backstabber.

Trivia

 * This item is a reference to the backstabbing mechanic in various video games, where backstabbing results in more damage done to the target. However, the mechanic of backstabbing is usually applied to melee weapons, not ranged weapons.
 * It may also be a reference to Judas' betrayal of Jesus.
 * Backstabber was originally an unofficial item which was supposed to showcase the modding capabilities of Afterbirth+ in the PAX 2016 livestream. However, all items included in the demo were later added to the final game.

Seeds
AL1K AYB4 (Tresure Room south of spawn) WNH6XF39 (Treasure Room at start) SJZG L9QW (Double Treasure rooms at spawn, bottom room; top room has Angry Fly)