Razor Blade

Razor Blade is an unlockable activated item.

Effect

 * On use, takes a full heart of health and grants +1.2 damage for the current room.

Synergies

 * Isaac cannot take damage from the Razor Blade, allowing for infinite uses of the item.
 * Isaac takes no damage while invincible, allowing for repeated free uses of the item.
 * Isaac loses half a heart instead of a full heart.
 * / : Isaac has a chance to drop a red heart while using the item.
 * 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 at the cost of health.
 * Panic Button: Self-damage occurs before enemy damage, making it almost impossible to lose Angel or Devil chance.

Interactions

 * No effect.
 * Shield/Invulnerability: Will not protect against this item's damage.
 * Using this item can make Tainted Samson unkillable, as his Berserk timer gains time when damaged, and he can't die from lack of red hearts during the rage.

Trivia

 * This item is used in Darkness Falls (challenge #4).
 * The item itself is a reference to the act of cutting one's self, usually at the wrists, to inflict self-harm or to commit suicide by loss of blood.
 * Isaac's appearance after using the item is just like the Dople.
 * In the original The Binding of Isaac, Razor Blade was unlocked by defeating Mom's Heart/It Lives as Eve.