This involves OTG because the logs say it tries to load dimensions that dont exsist, client falls into incorrect state, and crashes. In the logs and crash logs it says that an "errored" wolf was in an invalid place. I don't know what is causing this!!!

---- Minecraft Crash Report ----

WARNING: coremods are present:
Contact their authors BEFORE contacting forge

// Uh... Did I do that?

Time: 7/1/17 10:01 AM
Description: Initializing game

java.lang.NoClassDefFoundError: cep
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Unknown Source)
at java.lang.Class.getField0(Unknown Source)
at java.lang.Class.getField(Unknown Source)
at net.minecraftforge.fml.client.FMLClientHandler.detectOptifine(FMLClientHandler.java:310)
at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:217)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:440)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:352)
at net.minecraft.client.main.Main.main(SourceFile:124)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:236)
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:297)
at org.multimc.EntryPoint.listen(EntryPoint.java:162)
at org.multimc.EntryPoint.main(EntryPoint.java:53)
Caused by: java.lang.ClassNotFoundException: cep
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 23 more
Caused by: java.lang.NullPointerException
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182)
... 25 more

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

-- Head --
Thread: Client thread
Stacktrace:
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Unknown Source)
at java.lang.Class.getField0(Unknown Source)
at java.lang.Class.getField(Unknown Source)
at net.minecraftforge.fml.client.FMLClientHandler.detectOptifine(FMLClientHandler.java:310)
at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:217)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:440)

-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:352)
at net.minecraft.client.main.Main.main(SourceFile:124)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:236)
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:297)
at org.multimc.EntryPoint.listen(EntryPoint.java:162)
at org.multimc.EntryPoint.main(EntryPoint.java:53)

-- System Details --
Details:
Minecraft Version: 1.11.2
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_131, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 2974692496 bytes (2836 MB) / 3417833472 bytes (3259 MB) up to 4414504960 bytes (4210 MB)
JVM Flags: 3 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xms3200m -Xmx4736m
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML:
Loaded coremods (and transformers):
Launched Version: MultiMC5
LWJGL: 2.9.1
OpenGL: GeForce GTX 960M/PCIe/SSE2 GL version 4.5.0 NVIDIA 384.76, NVIDIA Corporation
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Resource Packs: 
Current Language: ~~ERROR~~ NullPointerException: null
Profiler Position: N/A (disabled)
CPU: 8x Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz

Hey, thanks for reporting this. Unfortunately I cannot see anything in this log referring to OTG, it looks like it's looking for a class called "cep", I have no idea what that would be. Can you reliably re-create this and if so, could you track it down to a single mod or mod combination?