Earlier I summoned a end dragon unaware of what happened with DoctorWhen, the server started getting really laggy, so laggy it took 30 seconds to eat one food, then the server began crashing (I'd say it crashed about 10 times).
After 10-15 minutes he got to less then half health then I died. The server was continuing to lag and I couldn't pick up my stuff so I just got some horrible armor and a axe, I then went back to the end and killed the dragon. After that, the lag stopped and I could finally eat again.

Long Story, Short: Do Not Summon The Ender Dragon