As I log in, The game crashes once I load a world.

Put the summary of the bug you're having here
When I log into a world, it always crashes before I get to the gameplay.
What I expected to happen was...:
I expected to play a world.

What actually happened was...:
When I chose my world to play, it loaded, then crashed as it was loading.

Steps to Reproduce:
1. Log in to 1.8.8 Minecraft
2. Choose an already saved world on single player
3. Wait as it loads, then crashes