All the issue in report file:

---- Minecraft Crash Report ----
// Hi. I'm Minecraft, and I'm a crashaholic.

Time: 03/10/20 16:23
Description: Initializing game

java.lang.NoClassDefFoundError: Could not initialize class net.minecraft.util.registry.Registry
at net.minecraft.item.ItemStack.lambda$static$3(ItemStack.java:77) ~[?:?] {re:classloading}
at net.minecraft.item.ItemStack$$Lambda$1164/1454366618.apply(Unknown Source) ~[?:?] {}
at com.mojang.serialization.codecs.RecordCodecBuilder.create(RecordCodecBuilder.java:72) ~[datafixerupper-4.0.26.jar:?] {re:classloading}
at net.minecraft.item.ItemStack.(ItemStack.java:76) ~[?:?] {re:classloading}
at net.minecraft.client.settings.HotbarSnapshot.(SourceFile:13) ~[?:?] {re:classloading}
at net.minecraft.client.settings.CreativeSettings.(SourceFile:30) ~[?:?] {re:classloading}
at net.minecraft.client.Minecraft.(Minecraft.java:394) [?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.client.main.Main.main(Main.java:149) [?:?] {re:classloading,pl:runtimedistcleaner:A}
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_51] {}
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_51] {}
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_51] {}
at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_51] {}
at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:51) [forge-1.16.2-33.0.61.jar:33.0] {}
at net.minecraftforge.fml.loading.FMLClientLaunchProvider$$Lambda$391/36627152.call(Unknown Source) [forge-1.16.2-33.0.61.jar:33.0] {}
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-7.0.1.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-7.0.1.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-7.0.1.jar:?] {}
at cpw.mods.modlauncher.Launcher.run(Launcher.java:81) [modlauncher-7.0.1.jar:?] {}
at cpw.mods.modlauncher.Launcher.main(Launcher.java:65) [modlauncher-7.0.1.jar:?] {}

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Thread: Render thread
Stacktrace:
at net.minecraft.item.ItemStack.lambda$static$3(ItemStack.java:77) ~[?:?] {re:classloading}
at net.minecraft.item.ItemStack$$Lambda$1164/1454366618.apply(Unknown Source) ~[?:?] {}
at com.mojang.serialization.codecs.RecordCodecBuilder.create(RecordCodecBuilder.java:72) ~[datafixerupper-4.0.26.jar:?] {re:classloading}
at net.minecraft.item.ItemStack.(ItemStack.java:76) ~[?:?] {re:classloading}
at net.minecraft.client.settings.HotbarSnapshot.(SourceFile:13) ~[?:?] {re:classloading}
at net.minecraft.client.settings.CreativeSettings.(SourceFile:30) ~[?:?] {re:classloading}
at net.minecraft.client.Minecraft.(Minecraft.java:394) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.main.Main.main(Main.java:149) [?:?] {re:classloading,pl:runtimedistcleaner:A}
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_51] {}
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_51] {}
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_51] {}
at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_51] {}
at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:51) [forge-1.16.2-33.0.61.jar:33.0] {}
at net.minecraftforge.fml.loading.FMLClientLaunchProvider$$Lambda$391/36627152.call(Unknown Source) [forge-1.16.2-33.0.61.jar:33.0] {}
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-7.0.1.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-7.0.1.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-7.0.1.jar:?] {}
at cpw.mods.modlauncher.Launcher.run(Launcher.java:81) [modlauncher-7.0.1.jar:?] {}
at cpw.mods.modlauncher.Launcher.main(Launcher.java:65) [modlauncher-7.0.1.jar:?] {}

-- System Details --
Details:
Minecraft Version: 1.16.2
Minecraft Version ID: 1.16.2
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 132853952 bytes (126 MB) / 234881024 bytes (224 MB) up to 2147483648 bytes (2048 MB)
CPUs: 4
JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
Launched Version: 1.16.2-forge-33.0.61
Backend library: LWJGL version 3.2.2 build 10
Backend API: NO CONTEXT
GL Caps:
Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'forge'
Type: Client (map_client.txt)
CPU:

Thank you! I tried to reproduce this crash but wasn't able to yet.
Could you post a list of mods you have installed?

Zero. Just forge and your mod:

Ohhhh! You have to install https://www.curseforge.com/minecraft/mc-mods/scalable-cats-force as it is a required dependency.
That error message is really confusing though. Maybe I can do something about that.

Well, it work! Ty <3