I joined my server that was recently updated to the 14w18a snapshot, and right as I joined the game crashed. Help?

Put the summary of the bug you're having here

What I expected to happen was...:
I was expecting to join the server and play on it.

What actually happened was...:
The game crashed right as I joined the game

Steps to Reproduce:
1. Open minecraft in 14w18a
2. Join the server.