Hidden Attributes

Tear Height[]

Tear height is a hidden attribute that determines how far above the ground tears travel, and in practice increases effective range. Very high tear height makes Isaac's tears' "cruising altitude" so high they can cross over obstacles as if they were spectral, but they won't go through the room walls. Once the tears fall down, they will start hitting obstacles again. This compounds with the starting height from the range stat.

Items that Affect Tear Height[]

Passive Items[]

Name	ID	Quote	Description	Quality
Blood Clot	5.100.254	DMG + range up	Tears fired from the left eye have +1 flat damage, +5 range, and +0.5 tear height.	2
Dead Onion	5.100.336	Toxic aura tears	Grants piercing and spectral tears. Increases tear size (without increasing damage) while greatly reducing range and shot speed.	3
Godhead	5.100.331	God tears	Grants homing tears with a damaging halo. +0.5 damage, -0.3 tears, +1.2 range, -0.3 shot speed, +0.8 tear height.	4
Ipecac	5.100.149	Explosive shots	Replaces tears with explosive and poisoning projectiles fired in an arc from the mouth.	4
Jesus Juice	5.100.197	Damage + range up	+0.5 damage, +0.25 range, +0.5 tear height.	2
Magic Mushroom	5.100.12	All stats up!	Makes Isaac bigger. Adds one Red Heart container, +0.3 damage, x1.5 damage multiplier, +5.25 range, and +0.3 speed. Restores all health on pickup.	4
Mini Mush	5.100.71	Speed + range up	Decreases Isaac's size, making him less likely to be hit. +0.3 speed, +1.5 tear height, -4.25 range (effective range is increased). +0.3 speed, +1.50 range.	2
Mom's Contacts	5.100.110	Freeze effect	+0.25 range. Adds a chance to shoot petrifying tears, which stop enemies in place and prevent them from moving or attacking.	3
Mom's Heels	5.100.30	Range up	+5.25 range, +0.5 tear height. Enemies that touch Isaac take 12 damage.	1
Mom's Lipstick	5.100.31	Range up	+5.25 range, +0.5 tear height. Spawns one random heart.	1
Mom's Underwear	5.100.29	Range up	+5.25 range, +0.5 tear height. Spawns 3-6 Blue Flies on pickup.	1
My Reflection	5.100.5	Boomerang tears	Gives Isaac's tears a boomerang effect. +1.5 range, +1 tear height, x1.6 shot speed multiplier.	0
Number One	5.100.6	Tears up + range down	Grants +1.5 tears, but severely reduces range.	2
Odd Mushroom	5.100.121	HP + DMG up, speed down	Grants one empty Heart container, +0.3 damage, +0.25 range, +0.5 tear height, and -0.1 speed.	2
Roid Rage	5.100.14	Speed and range up	+0.6 speed, +5.25 range, +0.5 tear height. +0.3 speed, +1.50 range, +0.5 tear height.	2
Sacred Heart	5.100.182	Homing shots + DMG up	Grants homing tears, x2.3 damage multiplier, +1 flat damage, +4.125 range, +0.75 tear height, -0.4 tears, -0.25 shot speed, a red Heart Container and replenishes all Red Hearts.	4
Safety Pin	5.100.339	Evil + range + shot speed up	Grants one Black Heart, +5.25 range, +0.5 tear height, +0.16 shot speed.	1
Synthoil	5.100.345	DMG + range up	+1 damage, +5.25 range, +0.5 tear height.	3
The Halo	5.100.101	All stats up	Grants one full Red Heart container, +0.3 damage, +0.2 tears, +0.25 range, +0.3 speed, and +0.5 tear height.	2
Tiny Planet	5.100.233	Orbiting tears + range up	Range up and makes shot tears revolve around Isaac until they drop.	0
Continuum	5.100.369	Transcendent tears	Grants spectral tears and increases range. Tears travel through walls and appear at the opposite side of the room.	2
Kidney Stone	5.100.440	Matt's kidney stone	Randomly while firing tears, Isaac will stop firing and turn red, where he will charge and release a lot of 'tears' in one go. The burst of tears also includes a kidney stone, which deals a lot of damage.	1
Marked	5.100.394	Directed tears	Isaac will automatically fire tears directed at a red target on the ground. The target can be moved with tear controls. +0.7 tears, +3.15 range.	0
Mom's Pearls	5.100.355	Range + luck up	+1.25 range, +0.5 tear height, +1 luck. Grants one Soul Heart.	2
Mr. Dolly	5.100.370	Range + tears up	+0.7 tears, +5.25 range, +0.5 tear height, spawns 3 random types of Hearts on the floor when picked up.	3
Purity	5.100.407	Aura stat boost	Boosts one of Isaac's stats depending on the color of the aura around him. The aura disappears upon taking damage and reappears with a random color upon entering a new room. Red boosts damage, blue boosts tears, yellow boosts speed, and orange boosts range.	2
Tractor Beam	5.100.397	Controlled tears	Increases Tears, Range, and Shot Speed. Isaac emits a beam from his face that his tears are bound to.	2
Compound Fracture	5.100.453	Bone tears!	Increases range. Tears turn into bones, which shatter into 1-3 bone shards upon hitting an enemy or obstacle.	2
Dark Prince's Crown	5.100.442	Loss is power	When at exactly one Red Heart, increases tears, range, tear height, and shot speed.	1

Trinkets[]

Name	ID	Quote	Description
Lazy Worm	5.350.66	Pft	Increases range by 4 and decreases shot speed by .4.
Tape Worm	5.350.65	Floooooooooop!	Doubles Isaac's range and halves his tear height.
Ouroboros Worm	5.350.96	Foop foop!	Tears travel in a large spiral pattern and become spectral, with a small chance to home.

Other[]

In co-op, Long Baby will occasionally briefly increase range, shot speed, and tear height. Dark Baby will occasionally briefly increase all stats, including tear height.
Azazel starts with -1 tear height, though the stat does not affect his short-range Brimstone.

Knockback[]

Knockback is a mechanic that determines how far an entity is pushed back by a certain force.

There are two kinds of knockback: directional and circular.

Directional Knockback[]

This knockback comes from Tears, most notably Isaac's. The knockback force is determined by the speed and direction of the tear, which itself is determined by Isaac's movement and stats. For example, Ring Worm does not increase the knockback stat, but does affect knockback as the tear's speed hits extremes of very fast and very slow; hitting enemies with the fastest moment of its arc applies significant knockback. (Needs research and confirmation)

Directional knockback affects most enemies, including bosses (except for stationary ones like Pin or Round Worm). Items (both trinkets and pickups) cannot be moved by tears, except for bombs placed by Isaac.

Items that Affect Directional Knockback[]

Passive Items[]

Name	ID	Quote	Description	Quality
Pisces	5.100.309	Tears up + knock-back shots	-1 Tear Delay, adds knock-back shots and increases tear size.	2
8 Inch Nails	5.100.359	Stick it to 'em!	+1.5 damage. Replaces Isaac's tears with nails, which have increased knockback.	3
Knockout Drops	5.100.637	They pack a punch!	Adds a chance to shoot a fist tear that has extremely high knockback and confuses enemies.	3
Terra	5.100.592	Born to rock	Replaces tears with rocks that deal variable damage, have increased knockback, and can destroy obstacles.	3

Trinkets[]

Name	ID	Icon	Quote	Description
Flat Worm	5.350.12		Blub blub!	Isaac's tears take on an oblong appearance. They also push enemies back.
Blister	5.350.77		Bounce back!	Increases knockback of tears.

Notes[]

Piercing shots from items like Sagittarius or Cupid's Arrow will remove the natural knockback from tears, but direct boosts still apply. Flat Worm increases only natural knockback and is thus nullified.
Knockback from tears provides minor crowd control for homing enemies like flies or Gapers, increasing the time it takes them to reach Isaac.
Be wary of the natural knockback from tears when trying to dodge charging enemies (like the smaller twin of Gemini, Gurglings, and Leeches): The tears can push them off-track and towards the direction you are planning to escape to.

Circular Knockback[]

This knockback is a little shockwave that's emitted at a certain radius in all directions, most prominently from explosives, like Bombs. Certain farts also create a (non-harmful) knockback. Some enemies, like the Fatty, can fart, and Isaac can also do so with the Butter Bean.

Pickups (including chests) are affected by circular knockback; items, however, are not.

Items that Cause Circular Knockback[]

Activated Items[]

Name	ID	Icon	Quote	Description	Quality
Butter Bean	5.100.294		Reusable knock-back	Upon use, Isaac farts and knocks back nearby enemies and projectiles. Enemies pushed into walls or obstacles take 12 damage.	0
The Poop	5.100.36		Plop!	Spawns a pile of poop where Isaac is standing and knocks back nearby enemies. May yield pickups like regular poop.	0

Passive Items[]

Name	ID	Icon	Quote	Description	Quality
Isaac's Heart	5.100.276		Protect it	Isaac himself is now immune to all damage, and a heart familiar follows him. If the heart is hurt, Isaac is hurt. The heart charges up as Isaac shoots, firing 8 blood shots, knocking back enemies, and leaving a puddle of creep when released.	0
Farting Baby	5.100.404		He farts!	Spawns a familiar that follows Isaac and blocks enemy shots. If a shot hits Farting Baby, it has a chance to fart, which charms, poisons, or knocks back nearby enemies.	1

Trinkets[]

Name	ID	Icon	Quote	Description
Butt Penny	5.350.24		Wealth of gas	Isaac will fart when he picks up a coin. Coins have a higher chance to drop from poops.
Mysterious Candy	5.350.25		Uh-oh!	Isaac farts or poops at random intervals. Getting hit can also trigger the effect.

Notes[]

There is also a mechanic that acts as an opposite of sorts to circular knockback: a gravitational pull that is emitted from Gaping Maws, Mega Fatty (while charging up its "Vomit Storm" attack), purple champion monsters, magnetic tears, and Suction Pitfalls.