Seeds, essentially random strings of characters, are used as the basis for all decision making in the game. By inputting a seed manually, you can guarantee that most randomly-generated decisions will occur the same every time. For instance, two players using the same seed will find the same items in the same locations.
Notes
- With the exception of some special seeds, inputting a seed will cause the 'no trophies' mark Template:NoUnlocks to appear. This prevents any achievements from being obtained on that particular run.
- Special seeds do not affect level generation.
- All alphanumeric characters are accepted except for 5, I, O, and U. On the PC version pressing the I, O, and U keys during seed entry will replace them with 1, 0, and V respectively.
- Template:Afterbirth Once a special seed has been entered, it will be permanently unlocked without needing to enter the code again. Pressing Q / Left Bumper during character selection will bring up the Easter Egg Section, in which any previously unlocked game mode can be selected. Selecting multiple modes at once is also possible.
Special Seeds
| Seed | Description | Effects |
|---|---|---|
| Miscellaneous | ||
| BASE MENT |
Infinite basements Template:NoUnlocks | The Basement repeats infinitely. |
| KEEP AWAY |
Tricky pickups Template:NoUnlocks | Pickups mimic Isaac's movements. |
| Template:Afterbirth G0NE S00N |
Pickups time out | Pickups quickly fade. |
| FREE 2PAY |
F2P version Template:NoUnlocks | Isaac starts with 69 coins, but all items and consumables must be bought. |
| PAC1 F1SM |
Pacifism Template:NoUnlocks | Enemies do not take damage. All doors stay open. When in a boss room, the boss's health slowly drains. |
| C0ME BACK |
Enemies respawn Template:NoUnlocks | Enemies, including bosses, respawn once Isaac leaves the room. Completing a room multiple times does not yield additional pickups. |
| Template:Afterbirth N0RE TVRN |
Point of no return | Boss rooms lock Isaac in similar to the Mom fight. |
| BRWN SNKE |
Poopy trail Template:NoUnlocks | Isaac leaves a trail of poop behind him as he walks. |
| Template:Afterbirth ALM1 GHTY |
Dog mode Template:NoUnlocks | Isaac is invincible. |
| K1DS M0DE |
Kids' co-op mode Template:NoUnlocks | Makes co-op babies invincible. |
| Curses | ||
| Template:Afterbirth DARK NESS |
Permanent darkness | Permanent Curse of Darkness. |
| Template:Afterbirth LABY RNTH |
Inescapable labyrinth Template:NoUnlocks | Permanent Curse of the Labyrinth. |
| Template:Afterbirth L0ST |
Hopelessly lost | Permanent Curse of the Lost. |
| Template:Afterbirth VNKN 0WN |
Forever unknown | Permanent Curse of the Unknown. |
| Template:Afterbirth MAZE |
Unending maze | Permanent Curse of the Maze. |
| Template:Afterbirth BL1N D |
Incurable blindness | Permanent Curse of the Blind. |
| Template:Afterbirth CVRS ED |
Horrible curse | Permanent Curse of the Cursed. |
| Curse Immunity | ||
| Template:Afterbirth N1TE L1TE |
Illuminate darkness Template:NoUnlocks | Provides immunity to Curse of Darkness. |
| Template:Afterbirth THRE AD |
Escape the labyrinth Template:NoUnlocks | Provides immunity to Curse of the Labyrinth. |
| Template:Afterbirth F0VN D |
I once was lost Template:NoUnlocks | Provides immunity to Curse of the Lost. |
| Template:Afterbirth N0W1 KN0W |
Know the unknown Template:NoUnlocks | Provides immunity to Curse of the Unknown. |
| Template:Afterbirth PATH F1ND |
Stay out of the maze Template:NoUnlocks | Provides immunity to Curse of the Maze. |
| Template:Afterbirth BRA1 LLE |
Heal the blind Template:NoUnlocks | Provides immunity to Curse of the Blind. |
| Template:Afterbirth BLCK CNDL |
Total curse immunity Template:NoUnlocks | Provides immunity to all curses. |
| Damage Modifiers | ||
| HARD HARD |
Full heart damage | Isaac takes a full heart of damage from all sources. |
| BRTL B0NS |
Twelve heart damage | Taking damage instantly kills Isaac. |
| D0NT ST0P |
Don't stop moving | Isaac takes damage if he stops moving. |
| THEG H0ST |
Damage on a timer | Every 45 seconds, a ticking will begin, and after 5 seconds, Isaac will take 1/2 heart of damage. Damage increases to 1 heart in the womb and below. Having invincibility during the time when damage should be inflicted prevents the damage. |
| 30M1 N1TS |
30 minute limit | Gives a time limit of 30 minutes to beat the game. When the timer hits 29:45, a timer starts ticking, and after 30:00, Isaac takes damage every second. |
| Control Modifiers | ||
| Template:Afterbirth 1CES KATE |
Ice physics | Makes the ground slippery. |
| Template:Afterbirth BRAV ERY |
Bravery | Isaac fires tears in the same direction that he moves. Removes the normal ability to fire tears. |
| Template:Afterbirth C0WR D1CE |
Cowardice | Isaac fires tears in the opposite direction that he moves. Removes the normal ability to fire tears. |
| DRAW KCAB |
Reversed controls | All movement and firing keys are reversed. |
| Template:Afterbirth AX1S ALGN |
Axis aligned controls | Isaac cannot move diagonally. |
| Camouflage | ||
| CAM0 K1DD |
Camouflage player | Isaac blends into the ground. |
| CAM0 F0ES |
Camouflage enemies | All enemies blend into the ground. |
| CAM0 DR0P |
Camouflage stuff | Pickups and items blend into the ground. |
| WH0A WHAT |
Camouflage everything! | Isaac, enemies, pickups, and items all blend into the ground. |
| 1MN0 B0DY |
Invisible player | Isaac becomes completely invisible. |
| BL1N DEYE |
Invisible enemies | All enemies become completely invisible. |
| Player Appearance | ||
| THEB LANK |
The blank | Isaac has no face. |
| KAPP A |
Grayscale | Isaac turns gray. |
| H0H0 H0H0 |
Christmas | Isaac wears a Christmas hat. |
| T0PH EAVY |
Big head mode | Isaac's head is large. |
| T1NY D0ME |
Tiny head mode | Isaac's head is small. |
| PTCH BLCK |
Black body | Isaac and his tears turn completely black. |
| Visual Effects | ||
| TEAR GL0W |
Glowing tears Template:NoUnlocks | Isaac's tears glow. |
| BL00 00DY |
Extra gore | Makes a lot more blood appear after enemies die. |
| HUD Modifiers | ||
| B00B T00B |
Cathode rays! | Applies a filter that makes the game look like it's being played through a cathode ray tube. |
| DYSL EX1A |
Dyslexia | All in-game text is rearranged. |
| KEEP TRAK |
No HUD | Removes the HUD entirely. This affects the map, health, consumables, held items, pickup text, floor names, and more. |
| MED1 C1NE |
Mystery pills | All pill names and descriptions show ???. |
| FACE D0WN |
Mystery cards | All card names and descriptions show ???. |
| Enemy Modifiers | ||
| CHAM P10N |
Champion enemies Template:NoUnlocks | All enemies turn into champions if possible. |
| C0CK FGHT |
Charmed enemies Template:NoUnlocks | All enemies are permanently charmed. |
| C0NF ETT1 |
Confused enemies Template:NoUnlocks | All enemies are permanently confused. |
| FEAR M1NT |
Scaredy enemies Template:NoUnlocks | All enemies are permanently scared. |
| FRA1 DN0T |
Skittish enemies Template:NoUnlocks | Every few seconds, all enemies become scared. |
| CLST RPH0 |
Asocial enemies Template:NoUnlocks | All enemies are permanently charmed and scared. |
| Sound Modifiers | ||
| FART SNDS |
Farty sounds | All sound effects are replaced with farts. |
| SL0W 4ME2 |
Movement tempo | Music speed is affected by Isaac's walking speed. |
| HART BEAT |
Health tempo | The lower Isaac's health is, the slower the music is. |
| ANDA NTE |
Downtempo | Music is slowed down. |
| LARG HETO |
Downtempo-- | Music is significantly slowed down. |
| ALLE GR0 |
Uptempo | Music is sped up. |
| PRES T0 |
Uptempo++ | Music is significantly sped up. |
Bugs
 Bug!
|
In the "BRWN SNKE" seed,if you combine a "stomp item" (e.g. Leo,Thunder Thighs...) with Petrified Poop,it will spawn a lot of Pickups.After a long time spawning pickups,the game will rarely crash. |
|---|
Trivia
- Many of the special seeds can be found by using either the Fortune Teller or the Rules Card.
- Some special seeds were shared with the community by the developers.
- If an item that would appear on a seed isn't unlocked yet, it will be replaced by another item that is unlocked.
Template:MasterNav