Gastrodon has two different forms: West Sea Gastrodon, which is pink and brown in appearance, and East Sea Gastrodon, which is blue and green. They are found on the respective sides of Sinnoh's mountain range.
Gastrodon is a sea slug-like Pokémon. Much like its pre-evolved form, it has a slug-like body with a round head and a mantle covering the top half of its body. It has six stubby legs and two black eyes with white pupils, with a mark imitating a third eye appearing on its forehead. A yellow stripe runs along the edge of its mantle, through its two lower eyes, and around the back of its head. Like Shellos, Gastrodon has two forms based on the sea it lives in.
In its West Sea form, it has a pair of large tentacles on its head that curve upward and a smaller, straighter pair on its neck. Its underside is pink, while its mantle is brown, with three pink spots on each side of its back. There are also two lumps on its back, resembling the cerata on real-life sea slugs.
In its East Sea form, it retains the head tentacles it had as a Shellos, which are now fully green and angled slightly further upward. Its underside is turquoise, while its mantle is forest green with two turquoise spots on each side. It has a pair of yellow, fin-like cerata on its back and a wavy yellow line bordering its side and rear.
Gastrodon and its pre-evolution Shellos are examples of allopatric speciation, although the two forms can still breed with each other. It is also a relative of Shellder and Cloyster. When threatened, it oozes a purple liquid and flees. While not poisonous, the fluid is very bitter and sticky. Its mucus-coated body is soft and squishy yet surprisingly resilient, and it leaves behind a trail of sticky slime when moving on land. It also has strong regenerative capabilities that allow it to recover from injuries or dismemberment within a few hours. In ancient times, it had a shell on its back, which gradually became a thin yet hard vestigial plate.
Gastrodon lives in shallow tidal pools, beaches, and rocky shorelines. Its diet consists mainly of plankton, but it is occasionally known to move onto land to look for other foods, such as beach sand. When it finds prey, it melts it with mucus before eating them. While Gastrodon cannot stay out of water for too long due to its body being highly vulnerable to dehydration, it becomes more active during cloudy or rainy weather. It has been found on far-off mountains during times of constant rain. The two forms of Gastrodon are known to engage in heated conflict with one another. West Sea Gastrodon was much more numerous in the past than it is in the present. Conversely, East Sea Gastrodon's population has visibly increased in population as of late.
Forms
Gastrodon has two separate forms: West Sea Gastrodon and East Sea Gastrodon. The two forms are purely cosmetic, and do not affect base stats or level-up moves.
Gastrodon has two different forms: West Sea Gastrodon and East Sea Gastrodon. In most cases, where it is encountered in the wild determines its form. This is purely a cosmetic difference, and this Pokémon cannot change between forms.
West Sea Gastrodon is pink and brown in color, whereas East Sea Gastrodon is blue and green. There is also a slight difference in shape depending on the form.
In Sinnoh and Hisui, West Sea Gastrodon is encountered west of Mount Coronet, while East Sea Gastrodon is encountered east of Mount Coronet. In Paldea, West Sea Gastrodon is encountered in Casseroya Lake, while East Sea Gastrodon is encountered in North Province (Area One); both forms can also be found in Tera Raid Battles regardless of location. In other regions, only one form appears in the wild per game (with the other only obtainable via trading or transfer): Gastrodon only appears in its West Sea form in Kalos's Friend Safari, and in Alola and Galar, only East Sea Gastrodon appear in the wild.
Gastrodon, the Sea Slug Pokémon and the evolved form of Shellos. Gastrodon inhabits the shallow tidal pools of the ocean, and its sturdy shell serves to protect its body.
Gastrodon, the Sea Slug Pokémon and the evolved form of Shellos. A sturdy shell covered Gastrodon's back long ago. Its cells still contain evidence of it today.
In Diamond and Pearl, no in-game Trainer uses East Sea Gastrodon in battle, even on the east side of Mount Coronet.
Prior to Generation VI, Gastrodon's shape was .
Gastrodon and its pre-evolution were accidentally released in Pokémon GO on April 29, 2019, but were removed shortly after. On May 17, 2019, they made their official debut along with various other Pokémon from Generation IV.
The Pokémon Scarlet and Violet Pokédex entries mentioning a decrease in West Sea Gastrodon and an increase in East Sea Gastrodon may be an inverse on the changes in the populations of real life sea slug species due to climate change — with species that better survive in warmer waters becoming more common.[2]
Origin
Gastrodon is based on a sea slug,[1] perhaps one of the order Opisthobranchia. It may also be based on a sea hare, a type of sea slug that is also known to secrete purple fluid in self-defense. The tentacles on Gastrodon's head are shaped like cattle horns, which may be a visual pun on 海牛 umiushi (Japanese for sea slug, derived from 海 umi (sea) and 牛 ushi (cow; cattle)).
Name origin
Gastrodon may be a combination of gastropod or Gastropteron (genus of sea slug), and don (Spanish for lord) or -don (common suffix in dinosaur names derived from the Ancient Greek word for tooth).
Tritodon may be a combination of Tritoniidae (family of shell-less marine gastropod molluscs) or Triton snail (marine gastropod mollusk named after Triton, Greek god of the sea), and don (Spanish for lord) or -don (common suffix in dinosaur names derived from the Ancient Greek word for tooth). It may also be derived from torito (Spanish for little bull).