Considering future scientific discoveries, the geneticist J.B.S. Haldane wrote “the Universe is not only queerer than we suppose, but queerer than we can suppose.” But that statement applies as much to the past as the future. As paleontologists continue to chip away at the fossil record they are continuing to find organisms that no one ever could have ever expected. And if life on Earth can be so strange, what might these creatures mean for different evolutionary paths taken on other planets? As you go about inventing fauna for your own sci-fi worlds, here are some mind-bending critters to keep in mind.