Freeze

I was going to a cave I recently found on a donkey fitted with both saddle and pack when my minecraft kept on freezing again and again. The controls like jumping and looking around and pausing were available but all movement was stuck and breaking blocks result in no drops. I had to restart my computer because for a 3rd time it completely froze both minecraft and my computer. I got no crash reports to attach but I'll try to recreate it in both 1.6.2 and 1.6.1.