So I was recently messing about on some of the server and found that the Be Jack Walker item. If bought would crash the server. I hope that this get's fixed soon!
Edit: News apparently the taunts menu, when used will crash the server as well. Using both the console command and the in game chat command's menu will crash the server. I didn't want to go on any occupied servers to do any test seeing as that is the community staff's job.