Pikachu nudibranch (Thecacera sp) - This colorful marine mollusk is part of the Thecacera genus of sea slugs. It is nicknamed for its resemblance to the adorable character, Pikachu, from the Pokémon franchise. At just 2cm, this Pikachu nudibranch is not easy to spot. Sightings are rare but are known to occur around Indonesia, Borneo, Western Australia and Japan. We photographed this Pikachu nudibranch while diving off the coast of Sekotong in Lombok, Indonesia. Read more in our post, A Scuba Diver's Guide to Lombok, Indonesia.