Osage Orange / Maclura Pomifera

The fruit has a pleasant and mild odor, but is inedible for the most part. Although it is not strongly poisonous, eating it may cause vomiting. (from wikipedia)

All I can think of, is brain. It probably has something to do with the fact, that I was just learning about the brain development in one of my classes.

Remember, don't eat green brains; they may cause vomiting.