Well the most rarest thing that I have ever heard of and seen just once has by far been “The Stone Plant”! on the exibhit at Gardens by the bay, Singapore. These plants actually looked like stones and if not pointed out, one would never be able to spot them.
Here is the picture of these extraordinary camouflage. Mother nature has so many ways and mechanisms of protecting and this is just one of them. Spot it if you can 😉 – well I did focus it for it to be visible 🙂