Most exoctic species

Top ten list of the most exotic life forms you have heard of? What time period do they belong to?

Moderator Action

Since this is an informal poll, it belongs in IMHO.

Moving thread from General Questions to In My Humble Opinion.

As I said in the thread that got locked, I’d go for something like this that is resistant to radiation, dehydration, cold, acid, vacuum, and even makes it into the* Guinness Book of Records* :).

The tuatara (which famously has a third eye, complete with its own lens and cornea and retina) “is considered the most unspecialised living amniote” as per wiki, which adds that “their rate of molecular evolution has been the fastest of any animal yet examined” and that they were “regarded as the messengers of Whiro, the God of death and disaster”.

Tell me that’s not what you’d write if you were coming up with a movie monster.

("Their dentition, in which two rows of teeth in the upper jaw overlap one row in the lower jaw, is unique among living species … They are able to hear, although no external ear is present, and have a number of unique features in their skeleton, some of them apparently evolutionarily retained from fish.". They’re just, like, weeeird.)

How can they be unspecialized if they have evolved so much?

That would seem to mean they are less evolved than other reptiles. Google the phrase “most unspecialised living amniote” and it pops up in every article about the Tuatara.

Thylacosmilus, the gigantic South American sabre-toothed opossum.

Desmostylus, the so-called “sea-pig”. Nobody knows if it was herbivorous like a manatee or a shellfish eater like a walrus. Or maybe both.

Thylacoleo. Yes, the marsupial lion of Australia. Except it was more like a giant carnivorous arboreal phalanger. So more like a leopard than a lion. You’ve heard of drop bears? This could have been a drop bear.

Or the Diprotodon. Take a wombat and expand to rhinoceros size.

Fuck, forget the extinct creatures. What about 90% of the extant animals of Australia. Your Platypus. Your Echidna. Your Bandicoot. Your Koala. Your Sugar Glider. Your Antechinus. Your Numbat. Your Honey Possum. Your Marsupial Mole. Your Tree Kangaroo.

The OP is asking about life forms, not just animals. So I’ll just add radiotrophic fungi, which literally derive their energy from gamma rays. They’re living pretty well in the main reactor chamber at Chernobyl.