| 2 rooms|
|(page 5, column 1, line 1)
| Defeat Delirium as EveDull Razor|
Dull Razor is an unlockable activated item added in Afterbirth †.
- Hurts Isaac without taking away health, activating any items that trigger upon taking damage.
- A Missing Page5% chance to induce The Necronomicon's effect upon taking damage.: May trigger A Missing Page, triggering the effect of The NecronomiconDamages all enemies in the room significantly..
- Anemic+5 range. After Isaac is damaged, a trail of red creep will be left behind Isaac until he leaves the current room.: Triggers the Anemic effect, giving Isaac more range and a trail of red creep.
- AthameWhenever Isaac takes damage, a black ring briefly appears around Isaac, dealing damage to all nearby enemies.: Triggers Athame, giving a large black ring around Isaac similar to Maw of the Void+1.0 Damage Up. After continuously firing tears for 2.5 seconds, a red cross appears on Isaac's head that, upon releasing the fire button, creates a black ring that rapidly deals damage equal to Isaac's tear damage to any enemies in contact with it..
- Bag LunchTaking damage has a small chance to destroy the trinket and spawn Lunch.: May trigger Bag Lunch, spawning an item pedestal with LunchAdds 1 heart container. on it.
- Best BudWhen hit, summons a white attack fly similar to Distant Admiration for the current room.: Will trigger the Best Bud effect, giving an orbital fly for the rest of the room.
- BetrayalEvery time Isaac takes damage, a charm effect is applied to every enemy in the room, causing them to attack each other rather than Isaac.: Will trigger, charming every enemy in the room.
- The Black BeanWhen taking damage, Isaac farts, causing poison damage to all enemies in range.: Will trigger, creating a poisonous fart affecting any enemies in its range.
- Blind RageIncreases invincibility time after getting hit.: Will trigger, increasing the duration of Dull Razor's invincibility.
- Bloody LustIncreases damage as Isaac receives damage. Damage increase stays for the whole floor.: Will trigger the Bloody Lust effect, giving the player a damage up for the rest of the floor.
- BozoIncreases damage by a flat 0.1 and grants a soul heart. Enemies can randomly become briefly charmed or feared. Taking damage has a chance to spawn a rainbow poop.: May trigger the Bozo effect, spawning a rainbow poop under the player's feet.
- Broken RemoteTriggers the Teleport effect whenever an activated item is used.: Will trigger the Broken Remote effect.
- Butter!Using an active item will drop it onto a pedestal on the ground. Taking damage may result in dropping a passive item.: May trigger the Butter!, very rarely, dropping one of your passive items
- Cambion ConceptionAfter taking damage a certain amount of times, a permanent demonic familiar spawns.: Using it counts as damage taken for the purpose of generating new familiars.
- CancerAdds 3 soul hearts. Grants The Wafer effect for the current room upon taking damage.: Will trigger, giving The WaferAll sources of damage that would cause more than one half heart of damage are reduced to one half heart instead. effect for the room.
- CartridgeChance to trigger The Gamekid effect upon taking damage.: May trigger Cartridge, giving Isaac the effect of The GamekidUpon use, turns the character into a into a Pac-Man-like creature for 5 seconds, granting invulnerability, inflicting fear on all enemies, and replenishing half a red heart container for every two enemies killed..
- Celtic CrossGrants a chance to trigger the Book of Shadows effect upon taking damage, creating a shield that nullifies all types of damage for 7 seconds.: May trigger Celtic Cross, giving Isaac the effect of the Book of ShadowsUpon use, creates a protective shield nullifying all types of damage for 10 seconds..
- Cracked DiceWhenever Isaac gets hit, there is a chance that the effect of The D6, D8, D12, or D20 gets activated.: May trigger the effect of Cracked Dice, triggering the effects of The D6Allows Isaac to re-roll collectible items in the current room into other items, depending on the current room's Item Pool., D20Rerolls all pickups in the current room., D8Re-rolls Isaac's speed, range, tears, and damage., or D12Re-rolls all rocks in the current room into other random objects, such as bomb rocks, metal blocks, TNT, or poops..
- Curse of the TowerCauses Isaac to spawn 6 troll bombs on the floor every time he gets hit, similar to the Anarchist Cookbook mechanic.: Will trigger Curse of the Tower, spawning troll bombs.
- Cursed EyeGrants charged tears that can be fired in a tight burst of four. Getting hit while charging will teleport Isaac into another room.: Will trigger Cursed Eye's teleportation effect if Isaac is charging tears while using Dull Razor.
- Cursed SkullIf Isaac has less than one full red heart after taking damage, he will be immediately teleported to the last cleared room he was in.: Will trigger Cursed Skull's teleportation effect if Isaac has half a heart of health.
- Dead BirdSpawns a flying familiar for the current room that chases enemies whenever Isaac takes damage.: Will trigger the Dead Bird effect.
- Fanny PackHas a chance to drop a random pickup when Isaac takes damage.: Will trigger the Fanny Pack effect, dropping a random pickup on the floor.
- Finger BoneGrants a chance to gain a bone heart upon taking damage.: May trigger, giving Isaac a bone heart.
- Fish HeadSpawns a blue fly every time Isaac takes damage.: Will trigger, spawning a blue fly.
- GimpyHas a chance of spawning a soul heart or black heart when taking damage. Enemies have a chance to drop a Half Red Heart after being killed.: Might trigger the effect of Gimpy, spawning soul hearts or black hearts.
- HabitWhen Isaac is hit, 1 point of an item's charge is filled. + SchoolbagAllows Isaac to hold two active items.: Will trigger the effect of Habit, granting 1 charge to the item in the Schoolbag. It will not grant any charge to itself this way, however.
- Habit + Schoolbag + DiplopiaDuplicates all pickups and item pedestals in the room. + 9 VoltReduces the charge of any Activated Items by 1. Any 1 charge items instead have timed recharges./ Car BatteryCauses Isaac's activated item to activate twice on each use.: If a second Dull Razor is in the Schoolbag, it will gain charge when the first Dull Razor triggers Habit. With 9 Volt or Car Battery, the other Dull Razor will be fully charged. This allows infinite use of the two Dull Razors by swapping between them, granting perpetual invincibility.
- HabitWhen Isaac is hit, 1 point of an item's charge is filled. + The BatteryActivated Items can be "overcharged" to allow for an additional use. + Car BatteryCauses Isaac's activated item to activate twice on each use. + : Instantly recharges on use, granting perpetual invincibility.
- Holy WaterWhen Isaac receives damage, the bottle breaks and a puddle of blue creep forms, which damages non-flying enemies, similar to Lemon Mishap. The bottle is reformed upon entering a different room.: Will trigger the Holy Water effect, spilling damaging blue creep on the floor.
- Infestation1-3 Blue flies randomly spawn every time Isaac gets hit.: Will trigger the effect of Infestation, spawning Blue Flies.
- LeprosyUpon taking damage, grants a body part as an orbital, which blocks enemy shots and deals 7 damage per tick to enemies it comes in contact with. The orbitals will be destroyed if they take enough damage from enemies or enemy shots.: Will trigger, adding a Leprosy orbital.
- MarblesSpawns 3 random trinkets. Taking damage has a small chance to swallow Isaac's currently held trinket, gaining its effect permanently.: May trigger, swallowing Isaac's currently held trinket and permanently gaining its effect.
- Milk!A glass of milk follows Isaac and spills on the floor upon taking damage. After the milk spills, Isaac's tear delay is decreased by 2 for the rest of the room.: Will trigger the effect of Milk!, giving Isaac -2 tear delay for the rest of the room.
- Missing Page 2Gives 1 black heart. Upon taking damage that reduces Isaac's health to one heart or less, activates The Necronomicon effect, dealing 40 damage to all enemies in the room.: Will trigger the effect of Missing Page 2 if Isaac's health is at or below one heart of health, causing the effect of The NecronomiconDamages all enemies in the room significantly..
- My ShadowEach time Isaac takes damage, inflicts fear on all enemies in the room and spawns a black Charger familiar that will attack enemies. The Charger will be killed if it is damaged too much.: Will trigger, causing fear on all enemies in the room.
- Mysterious PaperHas a chance to replicate the effects of A Missing Page, The Polaroid, The Negative, or Missing Poster.: May trigger the effects of A Missing Page5% chance to induce The Necronomicon's effect upon taking damage., The PolaroidIf the character has half a red heart or no red hearts after taking damage, it triggers the Book Of Shadows effect, creating a shield that nullifies all types of damage for 5 seconds. Also allows entrance into The Chest., or The NegativeIf the character has half a red heart or no red hearts after taking damage, it triggers The Necronomicon effect, damaging all enemies in the room. Also allows entrance into the Dark Room..
- Mystery EggSpawns an egg familiar, which cracks and turns into a random charmed enemy when Isaac is hurt. The egg regenerates upon entering a different room.: Will trigger Mystery Egg, spawning a random charmed enemy.
- Old BandageAdds one empty heart container. Whenever Isaac takes damage there's a chance that a Red Heart may drop.: May trigger the effect of Old Bandage, dropping a red heart on the floor.
- Piggy BankGives 3 pennies on pick-up. Every time Isaac is damaged, he will drop one additional penny.: Will trigger the Piggy Bank effect, dropping coins.
- PurityThis item will boost one of Isaac's stats depending on the color of the aura around him. The aura will disappear upon taking damage and will reappear with a random color upon entering a new room. A red aura boosts damage, a blue aura boosts rate of fire, a yellow aura boosts speed, and an orange aura boosts range.: Will trigger, changing the aura around Isaac once he enters the next room (can be useful.)
- Red PatchGrants a chance of increasing damage by 1.8 for the current room upon taking damage.: May trigger Red Patch, giving a 1.8 damage up for the rest of the room.
- ScapularOnce per room, when Isaac is reduced to his last half red Heart, the aura around his head temporarily vanishes and he is granted one Soul Heart.: If Isaac is at half a heart and Scapular has not already triggered this room, Dull Razor will trigger Scapular, giving Isaac a Soul Heart.
- Shard of GlassUpon taking damage, Isaac has a chance to drop a full red heart, gain 5 range, and leave a trail of damaging red creep for the current room.: May trigger the effect of Shard of Glass, giving a chance to drop a full red heart, or a chance to gain the effect of Anemic+5 range. After Isaac is damaged, a trail of red creep will be left behind Isaac until he leaves the current room..
- Smart FlyAfter Isaac takes damage, this fly will deal continuous touch damage to whatever enemy caused the damage until it is dead. The fly will then systematically attack 1 enemy at a time until the room is cleared.: Will trigger Smart Fly, causing the fly to chase enemies.
- Stop Watch Automatically inflicts slow to all enemies in every room.
Upon taking damage, inflicts slow to all enemies for the current room.: Will trigger Stop Watch, slowing all enemies in the room.
- Swallowed PennyUpon taking damage, Isaac drops a penny.: Will trigger Swallowed Penny, dropping a coin.
- TonsilWhen hit, there is a small chance a removed tonsil familiar starts following Isaac, blocking enemy shots.: May trigger the effect of Tonsil, creating a Tonsil orbital.
- Umbilical CordWhen Isaac's health is brought to half a red heart and no soul hearts, a Little Steven familiar spawns for the current room.: Will trigger at half a heart, spawning a Little StevenSpawns a familiar that follows Isaac around and fires homing tears. familiar for the rest of the room.
- Varicose VeinsTaking damage releases a ring of 10 high damage tears.: Will trigger Varicose Veins, activating an effect similar to Tammy's HeadShoots 10 tears in a circle around Isaac, which retain the damage, shot speed, and special effects (such as poison) of Isaac's tears..
- VirgoGrants a chance to trigger the Book of Shadows effect upon taking damage, creating a shield that nullifies all types of damage for 10 seconds. Also converts "bad pills" into "good pills".: May trigger Virgo, giving Isaac a chance to activate the effect of Book of ShadowsUpon use, creates a protective shield nullifying all types of damage for 10 seconds..
- WalnutTaking damage has a small chance to destroy the trinket and spawn various pickups.: May trigger the effect of Walnut, which may drop a random trinket, coin, heart, or key.
- Wish BoneTaking damage has a small chance to destroy the trinket and spawn a random item.: May trigger the effect of Wish Bone, creating an item pedestal from the current room's item pool.
- Cone HeadGrants a soul heart. Adds a chance to block enemy shots. / InfamyChance to block projectiles coming from any direction. / Metal PlateAdds a chance to reflect enemy shots. Grants one soul heart.: Can block the effect of Dull Razor, wasting it.
- Crown of LightGives Isaac a crown that glows blue when active, and turns gray when inactive. While Isaac has no empty red heart containers, Isaac's tears are replaced with blue diamond tears that deal double damage. Regardless of health, the crown will deactivate for the current room when Isaac takes damage.: Disables Crown of Light for the current room.
- Holy MantleAutomatically negates first taken damage in every room.: Triggers the Holy Mantle, wasting the Holy Mantle's effect for the room.
- Isaac's HeartIsaac himself is now immune to all damage, and a heart familiar appears and follows Isaac. If the heart is hurt, Isaac is hurt.: Completely nullifies the effect of Dull Razor.
- As using the Dull Razor will make Isaac invincible for a moment, this item can be used to enter Curse Rooms without taking damage.
- This item has a particularly wide range of synergies with other items.
- The item works almost identically to the Voodoo Pin in Antibirth.