I was playing and a skeleton shot at me and it just crashed. I reloaded the game and went in. Sure enough it crashed again. I put the old 50b snapshot and it worked just fine and got shot without crashing.
Environment
Macbook Pro early 2011
Java 1.7 i think
intel hd 3000
intel i7 2.8ghz
Duplicate of MC-4872. Please check before posting in the future. Also note that this issue has already been fixed and requires a fresh download of the snapshot.