I just found out about Kopi Luwak, marketed as the world's rarest, most expensive coffee. It is made from coffee beans excreted by the Luwak (civet cat), which feeds on the coffee cherries.
Originally, the bean was harvested naturally, which is why it was so rare. However, increased popularity means that now Luwaks are being captured, and force fed the cherries to provide the supply to meet the increased demand. Personally, I was horrified by this idea, so I wanted to share to help raise awareness of this atrocity.