The Atretochoana Eiselti
This might be the most NSFW image on this list of animals, so you may want to continue scrolling if you’re not at home right now. The atretochoana eiselti is also called the “penis snake” for a very good reason. A resident of the Amazon and Madeira Rivers, this eyeless amphibian isn’t really a snake at all. It has a long snake-like body with the earthworm-like rings along its body. And who could forget the odd shape of its head? It definitely resembles the male human anatomy, which probably made it quite shocking to those who first spotted this creature.