EDIT: This seems to be fixed as of 16w32b.

I'm not sure whether this counts as a dupe of MC-106032 or not, as MC-106032 only talked about pumpkins and was resolved with "Cannot reproduce".

The game won't crash when the pumpkin/witherskull is dispensed on a structure that is used to create an iron golem/snow golem/wither. If this is not the case, the game will crash.

How to reproduce:
1. Put a dispenser down
2. Put a pumpkin/witherskull in
3. Activate the dispenser