My Direwolf20 1.0.0 server was crashed by an Endoflame. It's not the latest version, but this bug hasn't been reported. The server is also using Sponge but it does not look like that is the problem here.

I can't be sure what crashed it exactly, since it is a server. Unfortunately, because of this, I am unable to reproduce the problem. Hopefully someone is able to figure out why this is happening from the log, but since I did not cause it I have no idea why it happened. The player who caused it is currently being interrogated, so I will update the report when I can.

Crash Report:
http://pastebin.com/haYPXAJR