Well - somebody. Not me. I do not do such things like clicking on unknown objects. And if I was it (to proof) then it was by pure hasard. Unwillingly.

---- Minecraft Crash Report ----

WARNING: coremods are present:
MalisisSwitchesPlugin (malisisswitches-1.12.2-5.1.0.jar)
MalisisCorePlugin (malisiscore-1.12.2-6.4.0.jar)
Inventory Tweaks Coremod (InventoryTweaks-1.64-dev.jar)
CTMCorePlugin (CTM-MC1.12-0.3.0.15.jar)
CoreMod (Aroma1997Core-1.12.2-2.0.0.0.b155.jar)
LoadingPlugin (RandomThings-MC1.12.2-4.1.7.jar)
No More Glowing Pots (nomoreglowingpots-1.0.jar)
CXLibraryCore (cxlibrary-1.12.1-1.6.1.jar)
llibrary (llibrary-core-1.0.6-1.12.2.jar)
BCModPlugin (backpacks+1.12.2+-+3.5.2.jar)
Contact their authors BEFORE contacting forge

// Hey, that tickles! Hehehe!

Time: 6/18/18 3:56 PM
Description: Updating screen events

java.lang.ArrayIndexOutOfBoundsException: 12000
at mrriegel.playerstorage.gui.GuiExI.func_146284_a(GuiExI.java:371)
at net.minecraft.client.gui.GuiScreen.func_73864_a(GuiScreen.java:443)
at net.minecraft.client.gui.inventory.GuiContainer.func_73864_a(GuiContainer.java:323)
at mrriegel.limelib.gui.CommonGuiContainer.func_73864_a(CommonGuiContainer.java:66)
at mrriegel.playerstorage.gui.GuiExI.func_73864_a(GuiExI.java:398)
at net.minecraft.client.gui.GuiScreen.func_146274_d(GuiScreen.java:533)
at mrriegel.limelib.gui.CommonGuiContainer.func_146274_d(CommonGuiContainer.java:85)
at mrriegel.playerstorage.gui.GuiExI.func_146274_d(GuiExI.java:433)
at net.minecraft.client.gui.GuiScreen.func_146269_k(GuiScreen.java:501)
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1757)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1096)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:397)
at net.minecraft.client.main.Main.main(SourceFile:123)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

You know what I mean. MC 1.12.2 Forge 14.23.3.2698 (because both newer versions crash without telling what is the offending mod) , PlayerStorage 1.12.2-1.3.1

The world is all new and everything is installed freshly because the old installation went "peaceful" from time to time. I re-installed MineCraft. Now there is something new and noooooooo ! I did not click it.

Edit: It is the potion effect "speed" which comes from Everlasting Abilities. Speed was given on startup as a random gift. Ok. Clicking again on it was a bad idea :)))