What are your favorite extinct species? Mine definitely has to be Platybelodon for the simple fact that it's an elephant with a snow shovel for a face.
Hallucigenia it's a relative of modern arthropods, Hallucigenia is one of the strangest creatures in the fossil record. Less than 3 millimeters long, it has a bulbous round head connected to its cylindrical trunk. Though it was previously thought that it stood on its spines, it was later discovered that the tentacles are actually feet, making the Hallucigenia the ancestor of today’s velvet worms.
Oh! Hallucigenia is another one of my favorites, along with Anomalocaris, Megalania, and Moschops!