Put the summary of the bug you're having here

What I expected to happen was...:

I was loading into my snapshot world like i normally do.
What actually happened was...:

However, as soon as i enter it a second later the game crashes. I tried this a few times and kept crashing. I switched to an older profile (uses 1.6.2) i play on and tried to load the main world i have on that profile, and the game crashes too, and this has been happening since the latest snapshot for 1.8, or the 1.7.10 . How its affecting the whole game, including profiles, I don't know. In short, yesterday it was working fine. Today, no.
Steps to Reproduce:
1. Log in to minecraft
2. Select any profile
3. Play the game
4. Select a world to enter
5. Crashes upon entry