Shellos is a Water type Pokemon introduced in Generation IV. It evolves into Gastrodon starting at level 30. Shellos have two different appearances: West Sea, pink and white, and East Sea, blue and green, found on the respective sides of Sinnoh’s mountain range. Take a look below for 25 fun and fascinating facts about Shellos.

1. Shellos is a slug like Pokemon whose appearance changes drastically depending on where it is found. However, both forms have a shell like back and an amorphous lower body.

2. Both forms also have yellow lining around their eyes, mouth, and back.

3. In the West Sea form, the underside is white and its shell is pink.

4. The shell has several small spike-like protrusions on it.

5. On its head is a ring of pink fleshy knobs resembling flower petals that spike up.

6. In the East Sea form, the underside is green and its shell is blue.

7. The shell has two flap-like protrusions.

8. These flaps are lined in yellow. 

9. On its head are two white-tipped knobs resembling horns that extend away from its face.

10. The Nurse Joy featured in Gateway to Ruin! revealed Mt. Coronet’s formation led to the allopatric speciation event, with the original population of Shellos being separated into two. As a result, Shellos’ color and other physical differences began to vary due to environmental differences and population isolation over time.

11. The two forms are still able to interbreed; the child takes the mother’s form or the father’s if bred with a Ditto.

12. If it is pushed or squeezed, a mysterious purple fluid will ooze out of its body.

13. In the anime, West Sea Shellos can extend their necks to incredible lengths.

14. It is unknown if the East Sea form can do this as well.

15. Shellos live along the sea shore.

16. According to an interview in Nintendo Power with Ken Sugimori, Shellos and Gastrodon were originally intended for Pokémon Ruby and Sapphire, but were not implemented due to time constraints.

17. Both Shellos and Gastrodon have early back sprites that can be found in the game data for Pokémon Diamond and Pearl; however, there are no front sprites for these forms.

18. In Pokémon Diamond and Pearl, no in-game Trainer uses East Sea Shellos in battle, even on the east side of Mt. Coronet.

19. Shellos’s English Pokédex entry for Pokémon HeartGold and SoulSilver has the fewest words of any Pokédex entry in the core series games, with nine. The Pokédex entry is carried over to Pokémon Y and Pokémon Alpha Sapphire.

20. Shellos is the only Pokémon with Sand Force that benefits from its Sandstorm immunity, since the other Pokémon are naturally immune to its damage due to their typing.

21. Shellos is based on a sea slug, more specifically the Chromodoris lochi.

22. Shellos may be a combination of shell and loss or lost (referring to its lack of a shell), or the German suffix -los (-less).

23. West Sea Shellos debuted in A Stand-Up Sit-Down!, under the ownership of Zoey, where it partnered with her Glameow to show Dawn and her Pokémon a Double Performance. In Last Call — First Round!, it was revealed to have evolved into a Gastrodon.

24. Multiple Shellos of both kinds appeared in Gateway to Ruin!, which also served as the main series debut for East Sea Shellos.

25. East Sea Shellos debuted in a cameo in The Rise of Darkrai.