Razor Blade

Razor Blade is an unlockable activated item.

Effect

 * Upon use deals one heart damage and grants +1.2 damage for the current room.

Synergies

 * Isaac's Heart: Isaac cannot take damage from the Razor Blade, allowing for infinite uses of the item.
 * The Wafer: Isaac loses half a heart instead of a full heart.
 * The Polaroid: Isaac takes no damage while invincible, allowing for repeated free uses of the item.
 * Whore of Babylon: The Razor Blade can be used to activate this item's effect by doing enough damage to get Isaac down to half a red heart (or one red heart as Eve), providing a big damage boost for the current room.

Trivia

 * This item is used in Challenge #4 (Darkness Falls).
 * The item itself is a reference to the act of cutting one's self, usually at the wrists, in order to inflict self harm or to commit suicide by loss of blood.