While building a Blaze grinder, as I exited and entered the world near many Blazes the game crashed a couple seconds after entering the world and taking a few steps. I began using about 50MB more memory each time I entered/exited a world.

Completely un-modded version. Using an animated 16x16 resource texture pack. Able to reproduce after reloading javaw.exe from launcher.

Steps to Reproduce:
1. Enter and exit a world in the Nether several times near approximately 80+ Blazes (judging from entity count)