Ambergris is whale intestinal secretions, but you'd never know how gross it is from its high profile in the world of perfumery. An excellent fixative with a sweet, earthy scent, the stuff has a long history of association with fragrance — and whale killling.
That's right, Captain Ahab didn't just want Moby Dick's blubber, he wanted his sweet, sweet ghost whale ambergris. Some ambergris gets left behind in the sea naturally when sperm whales throw it up, but it's traditionally been obtained from whales' abdominal cavities. Nowadays, there are plenty of synthetic alternatives, generally referred to as "amber" notes, but some fragrances still use the real ocean-sourced or even whale-sourced stuff. Most prominently, scents made by both Creed and Hermes are rumored to contain raw ambergris, but since their formulas are proprietary, nobody outside those houses knows for sure.