As using the Dull Razor will grant extra invincibility frames like normal damage, this item can be used to enter Curse Room for free, or, with proper timing, allow Isaac to avoid taking damage from an enemy or obstacle.
Dull Razor ignores shields granted by Holy Mantle, and similar items.
Synergies[]
Error: No Book of Virtues interaction found for "Dull Razor".
Car Battery: Dull Razor activates twice, triggering on-damage items twice.
Cambion Conception: Dull Razor triggers a damage, allowing for free familiar spawn on repeated use.
Interactions[]
For a full list of items that work with Dull Razor, see the list of damage triggered items. Note that any specific extra conditions the items may have for their activation still apply.
Habit + Schoolbag: The secondary item will be charged.
Habit + Schoolbag + 9 Volt: If Dull Razor is copied into the second active item through an effect such as Diplopia or Crooked Penny, the two Dull Razors can be switched between infinitely.
Habit + The Battery + Car Battery: Dull Razor will be charged, allowing for infinite uses of the item.
Isaac's Heart: Completely nullifies the effect of Dull Razor.
Perfection: Is not destroyed by a use of Dull Razor, as it counts as self-damage.
Purity: Cancels the current effect of Purity, allowing a different aura to be gained instead.
In-game Footage[]
Trivia[]
The item works almost identically to the Voodoo Pin in Antibirth.
The item will cost 10 cents if found in a 
Bug!
Habit will charge Dull Razor if Isaac has 
The Battery.
Eve Unlocks 
Delirium Unlocks 
The Binding of Isaac: Rebirth
