I was in the new water temple in creative mode and threw a Splash Potion of Harming at the Elder Guardian. When the Potion exploded the game crashed. The potion would have affected both the player and the Guardian. I restarted the world and I did the same thing and Minecraft crashed again. Both crash reports are attached.
Duplicate of MC-57112 - If you have not, please use the search function in the future, to see if your bug has already been submitted. If you could not find the original report, please comment with the keywords you searched for.