Viewing Mod
The Binding of Undertale
TBOI x Undertale Crossover Mod
Created 2 years ago

Get the AB+ version here:

Thank you very, very much for the Mod's overwhelming reception and 50000+ Downloads!

This mod replaces characters, music, bosses and floors with Undertale content! Enjoy!

by tipo19 and Opscat

Talk to us!

Q: Do I need Afterbirth for this to work?
A: No. Inside the folder, you can see there is a "Rebirth only" folder.

Q: Where's Toriel, Asgore and Chara?
A: You installed the Special version. Re-install the mod, but only Install the Basic version, not the Special one, and you'll get those characters.

Q: My game Crashes!
A: Install the mod, then delete Costumes2.xml. Be aware that this might cause characters to change appearence
when collecting some items.

Q: I'm in Snowy/Waterfall and the screen is pitch black!
How to fix:
Go inside resources/gfx/Background and delete the "Black" images. Those being: 8bitclouds_64,8bitclouds_64_black,8bitclouds_642,8bitclouds_643,blue_overlay and orange_overlay.

Q: I see a credits page, but not the Challenge page! Where is it?
A: If you want to see the challenges, just go inside gfx/ui/main menu and delete challengeph.png

Q: Is this compatible with Mac/Linux?
A: As far as we know, it's compatible with mac. It's super buggy with Linux and we plan on fixing of it later.

Q: I found a bug! Where can I report it?
A: Either Private Message me through Steam or the mod's blog.

Q: Can I suggest/submit stuff?
A: Yes! Either go to the mod's blog or post a comment in this comment section.

- The mod can be very glitchy on Linux and Mac.

- The Rebirth-only version is very early so expect glitches.
(Example: No Gaster Blaster. For some reason, rebirth ignores the familiar folder.)

_ In Snowy Rivershore and Waterfall, the screen might go black, but you can still hear the sound. Read the FAQ, you can find the answer there.

-Bugfix for Mac:

-More item reskins. (Taking Suggestions!)
-Waiting for Afterbirth+ !!!!

SwingPoynt v2:
iVertrox (Spanish):



Special Thanks to:
Patkall - Sprites
FAz - Sprites
SoaringSparrows - Original Concept
IKARUS - Song Credit
/u/Haylex - Tem Shop Mod
Draexzhan - Miscellaneous Item Sprites
reijigazpacho - Logo
Felix ( - Nightmare Sprites and the Omega Flowey boss
Sophomore - Miscellaneous Item Sprites
/u/otherhand42 - Miscellaneous Help
engineerthecowboy - Rebirth Testing
Toby Fox - Undertale


x 7788

- 20+ New items and 3 transformations, by the talented FAz!

- Community Update: 20+ items and a Flowey transformation, by the amazing /u/Patkall! Thank you!

- Fixed compatibility with the newest Isaac patch.

- More items

- New version whenever Afterbirth+ Hits

- Fixed Rebirth Compatibility

- Rebirth Support! (Thanks to engineerthecowboy for testing!)

- Community Made items!

- More items, like Muffet's Pet and Lil' Whimsalot!

- New character: Mad Dummy!

- Made it easier to understand how to install/know what version you're using.

- Small item replacements.

- Balanced some stuff.

- Fixed Special Version having a hybrid of Gaster and Temmie.

- Two New Characters, Gaster and Temmie.

- Two new end bosses, Omega Flowey and God of Hyperdeath Asriel

- HP up item reskins

- Some music added

- Napstablook now Starts with Dapper Blook

- Frisk starts with Purity (Soul Colors)


- Only a small amount of items now change your character.

- Asgore, Sans, Mettaton, Toriel, Asriel and Undyne have new costumes wich will help prevent their appearence to change.

- Fixed some naming stuff

- Made the Character menu less messy

- Toriel starts with proper items

- Blue womb is not dunked up anymore

- Characters don't have their items because you didn't unlock them was fixed

- Napstablook glitches when picks up a item was fixed

- Frisk doesn't have Isaac's heart, just <3

- Papyrus lost 1 heart container inside his spaghetti

- Mettaton has better bombs and Tech.5 (not tech 2)

I tried downloading on Mac but some of the sprites don't work, most notably the entire background for every floor. Some of the characters still work and so does the music, but other than that its completely broken.
it's so hard to get one of the older versions to work.
I come into this issue where when I download it, it opens an internet browser folder named the-binding-of-undertale_3.6.rar that I can't use. Could you help me?
Try opening the file with 7-zip or Win-Rar or something like that, then you should be able to copy and paste the files
how do I uninstall I want to play normal Isaac,chellanges get impossible with 1 hp
when its that year, i will try to come back
Cool mod! i've been watching vids about it and just bought the game,lol, but i can't wait to play it, good job on it!
Help my games have a bug, I think is a texture bug beacause undyne have a shield but she don't have spear, I have a rebirt version, if kill a mom a firts times ?
help me plz le jeux binding of issac me fait un encrant noir et me dit que le jeux a cesser de fonctionner
des que je lance binding of undertale le jeu se mes noir et après me dit: binding of Isaac a cesser de fonctionner
The Binding of Undertale
help!! I went to install it and its not working! how do I download and install it?
Well, perhaps you just didn't buy at least Rebirth.
hello, i have some trouble with this mod, only thing i get is backgound , new skin for character ( except dummy who still have dark isaac head) and flowey sound in top of devil room.
i didnt get undertale music, item, dummy full skin, timmy shop, and maybe other thing i dont know (i restart the game so i didnt unlock everything) does someone have a solution please ? thank you very much for any answer who can help me :0
By the way i play on rebirth version and i put rebirth mod on it.
So what's the difference between the "Rebirth-only" and the
"Afterbirth" version?
The Rebirth version only has Frisk, Asgore, Mettaton, sans, Toriel, Papyrus, Undyne, Mad Dummy and Gaster. It is also incredibly buggy. The Afterbirth version includes almost every Undertale main character, but Asriel, Monster Kid, and Muffet are in a separate character pack.
November 2, 2017 - 2 months ago

We now have a store with modding-related and Antibirth shirts, with designs by the amazing Elko! The price may be going up a little soon, so if you wanted to get them at the lowest price they will be, now is the time. Special thanks to DragonoidSlayer for helping get this set up!

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