Crash Report File: here
Code: here
Running
Minecraft 1.16.3
Forge 1.16.3-34.1.1
Java 1.8
Bookshelf 1.16.3:8.0.1

Take into consideration that this is my first time using a post 1.7.10 forge version.

You need to use fg deobf compile in the dependencies block, I would also recommend updating the MCP mappings to be the same.

https://github.com/OtisGoodman/Spooky-Stuff/blob/main/build.gradle#L71

compile fg.deobf("net.darkhax.bookshelf:Bookshelf-1.16.3:${bookshelf_version}")

MCP version is 20200916-1.16.2

ok sounds good

How do I update MCP mappings?

ty man

https://github.com/OtisGoodman/Spooky-Stuff/blob/main/build.gradle#L22