I was playing single player survival when I found an unloaded chunk. I tried to step into it to force it to load, but I ended up getting stuck in it. I saved and quit and came back. I was still in the chunk. So I changed my gamemode, and when I finally managed to get out, I saw hundreds of pigs (there were only a few of them initially) glitching around and jumping. I saved and quit again, then I tried to get back in. This time, I saw the loading screen then the main menu again. I tried to load the save again, and then Minecraft just froze.

Considering how the population of pigs around my house increased by around 10000%, I think the save file may be corrupted.

How to reproduce it?
I guess walking in a chunk in SSP should do it.

More information
I was using a texture pack.