Put the summary of the bug you're having here
I middle-clicked a dragon head on a redstone block and I wanted to get the dragon head back without going to the menu.
I middle-clicked it and the game closed and said 'Crash Report'.
Steps to Reproduce:
1. Place down a 'Dragon Head' from update '15w33c'
2. Get your crosshair over the 'Dragon Head' block and middle-click
3. Your game should've crashed and your game didn't save.
*I checked through it again and the same happened.