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 -0.3 Shot Speed, +0.8 Tear Height, and +1.2 Range. Grants homing tears with a damaging halo. +0.5 Damage, -0.3 Tears -0.3 Shot Speed, and +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 / +1.5 Range, and +0.3 Speed, and restores all Health.	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	Adds a Red Heart Container. Grants homing tears, a x2.3 Damage multiplier, +1 flat Damage, -0.4 Tears, -0.25 Shot Speed, and +4.125 Range. Adds a Red Heart Container. Grants homing tears, a x2.3 Damage multiplier, +1 flat Damage, -0.4 Tears, and -0.25 Shot Speed.	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	Massively increases Range and grants spectral tears. Tears orbit around Isaac at a fixed distance until they hit the ground.	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.	2
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.	1
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.	3
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.	3
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.	3
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 gain spectral, with a small chance to gain homing. Also adds +0.4 Tears.

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.

Tear 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 Shot Speed. 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. Damage does not affect the knockback.

Upon collision, the tear applies two seperate knockbacks on the enemy. One is collision knockback which pushes the enemy away from the tear. The other one is momentum knockback which pushes the enemy toward the tear's movement direction. Since they can have directional difference, the two knockbacks can cancel each other in some rare cases.

${\text{Collision Knockback}}={\frac {V_{p}\times K\times M_{p}}{10\times M_{t}}}$

${\text{Momentum Knockback}}={\begin{cases}M_{p}\times \left\vert {\frac {(V_{p}+K)}{M_{p}+M_{t}}}-{\frac {K}{M_{t}}}\right\vert ,&{\text{if the tear is not Piercing}}\\{\frac {M_{p}\times V_{p}}{M_{p}+M_{t}}},&{\text{if the tear is Piercing}}\end{cases}}$

Where:

V_p is the tear's velocity.
K is knockback multiplier, which is 1.7 by default but is counted as 0 when the knockback multiplier is not active.
M_p is the tear's mass, which is 8 by default.
M_t is the enemy's mass.

Knockbacks from laser is:

${\text{Laser Knockback}}={\begin{cases}1.8\times {\frac {M_{p}}{M_{t}}},&{\text{if the knockback multiplier is not active}}\\3.6\times {\frac {M_{p}}{M_{t}}},&{\text{if the knockback multiplier is active}}\end{cases}}$

The knockback multiplier does not affect lasers' knockback.

Knockback items affect the knockback in many ways, by activating the knockback multiplier, increasing the knockback multiplier, and/or increasing the tear mass. Effects that increase the knockback multiplier do not stack, and only the highest increase applies. Effects that increase the tear mass do not stack. Soy Milk or Almond Milk decrease the tear mass, thus weakening the knockback.

Items that Affect Tear 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
Soy Milk	5.100.330	DMG down + tears way up	Tears are smaller and do much less damage, but fire in very rapid succession.	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
Almond Milk	5.100.561	DMG down + tears up + you feel nutty	Quadruples fire rate, with x0.3 damage multiplier. Tears are given random worm trinket effects.	1
Terra	5.100.592	Born to rock	+1 Damage. Replaces tears with rocks that deal variable damage, have increased knockback, and can destroy obstacles.	3

Trinkets[]

Name	ID	Icon	Quote	Description
Blister	5.350.77		Bounce back!	Increases knockback of tears.

Notes[]

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 live bombs.
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.

Knockback from other sources[]

Various sources also can cause knockback. This knockback is often a little shockwave that's emitted at a certain radius in all directions, most prominently from explosives, like Bombs. Certain farts also create a knockback. Some enemies, like the Fatty, can fart, and Isaac can also do so with certain items.

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

Knockbacks from Belly Jelly, Butter Bean, Divine Intervention, Hemoptysis, and Knockout Drops are strong knockback. They do not decrease from the enemy's friction and linger for a relatively long time once applied. Any enemy affected by it takes 10 + 2 × (floor - 1) damage upon being pushed into walls or obstacles. No other knockback can deal such damage however strong it is.

Items that Cause Knockback[]

Activated Items[]

Name	ID	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.	1
The Bean	5.100.111	Toot on command	Isaac farts, poisoning any enemy in close range.	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	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
The Black Bean	5.100.180	Toot on touch	When taking damage, Isaac farts, causing poison damage to all enemies in range.	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
Belly Jelly	5.100.690	Bounce away!	Causes enemies to bounce off of Isaac, dealing damage to them if they hit an enemy or obstacle. Also gives Isaac the chance to deflect enemy shots.	3
Hemoptysis	5.100.726	Double tap sneeze	Double-tapping a fire button causes Isaac to sneeze blood, dealing damage to enemies in front of him.	2
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

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.