Pixelmon Server Crash 1.12.2

Brother was playing on a server we made and he says the pc crashed. I turned it back on and tried to start the server and It starts up to loading the world and then crashes. I’ve tried a few solutions on other threads with related issues but none worked.

The link to the crash log is here. Any help given is much appreciated!

Crash Log

Edit This is the crash log when I reverted and undid everything from the Crash Report Thread
Original Crash Log

Somehow the level_sponge.dat file was corrupted when it crashed - the log makes it clear that file is broken. There should be a level_sponge.dat_old backup file you can use to replace it, or (at worst) you can delete it entirely and let it regenerate (with some loss of Sponge specific data). Make sure you check all worlds - there will be a file for each, and they could all be broken…