[.009] Client crash when illusion block's mimic base is broken

[irkedIsaac]

Essentially when I broke the block my illusion block was mimicking, I saw a brief flash where it mimicked the block on top of it (a wood block) and immediately crashed afterwards.

http://pastebin.com/HngMnFvZ

[Pokang]

Same for me, now my game crashes every time the illusion block enters my rendering zone.

[TheIcyOne]

Can you try it without Optifine? I can't personally reproduce it.