On paper, Gastrodon looks underwhelming. In practice, Storm Drain redirects Water moves and boosts its Sp. Atk — and that's the whole story. Water/Ground typing means Electric moves can't touch it, and only a single type hits it super-effectively. Known as the Sea Slug Pokemon.
Gastrodon's spread is anchored by HP, with balanced defenses backing it up. Speed is the clear weak point. Worth 2 HP EVs per KO, and the medium-fast 1M XP curve keeps leveling painless.
Found more often on the land than in the sea. More active when it’s cloudy or rainy out than when the weather is fair.
Gastrodon Weakness
GoodGastrodon's Water/Ground typing leaves it vulnerable to Grass moves. Grass hits land at 4x, so they're the biggest threat. It shrugs off Electric-type attacks completely. It resists 4 types, giving it decent defensive coverage. Storm Drain grants an additional Water immunity, reshaping the matchup chart. With 111 HP and balanced defenses, Gastrodon can afford to eat a neutral hit or two.
Gastrodon is the evolved form of Shellos. Breeding produces Shellos eggs, and they're average hatch time. Evolving from Shellos gave Gastrodon the biggest boost in HP (+35), bringing the total to 475 stats.
How to Evolve
Breed with Gastrodon to get Shellos eggs easily using 19 partners from the Indeterminate and Water1 egg groups.
Stormdrain isn't flashy, but it matters. Combined with Leftovers for passive recovery each turn and max HP and Defense EVs, Gastrodon fills the defensive wall slot reliably. Calm nature finishes the spread.
Best Build
Legends: Arceus uses different battle mechanics.
Competitive build content is not applicable for this game. Select a main series game for builds.
Gastrodon's movepool balances level-up moves with TM options. Consistent STAB comes from Hydro Pump and Earth Power, and Normal and Rock coverage and more keeps opponents from switching in for free. No major gaps here.
Level-Up Moves
TM Moves
Egg Moves
Tutor Moves
Gastrodon starts showing up in mid-game routes at decent spawn rates across 3 encounter spots. The list below is sorted so you can pick what fits your current progress without scrolling through everything.
Where To Catch Gastrodon in Legends: Arceus
Shellos is your first catch on the way to Gastrodon. You'll find walking encounters from walking across 7 total spots in the chain.
Step 1Catch ShellosEASYRamanas IslandGrassUncommonWaterEASYSandgem FlatsGrassUncommonDesertEASYSeagrass HavenGrassUncommonEASYTranquility CoveGrassUncommon- Step 2Gastrodon ✓EASYRamanas IslandGrassUncommonWaterEASYSandgem FlatsGrassUncommonDesertEASYSeagrass HavenGrassUncommonor evolve from Shellos (Step 1)
Don't let Gastrodon's 475 base stat total fool you. Storm Drain is what makes it tick — it punches way above its weight class. We rate it B-Tier as a support.
Watch for Roserade (Grass) when using Gastrodon. They all hit it super-effectively with STAB. Roserade is the most dangerous since Grass moves deal 4x damage. Only 1 weakness means fewer dedicated counters to worry about. At base 39 Speed, Gastrodon won't outrun any of these threats so switching to a resist is usually the safer play.
Shellos evolves into Gastrodon at level 30. Gastrodon is the fully evolved form. It sits at 475 BST in its evolved form.
Run Storm Drain on Gastrodon. It's the ability that defines how you build around it and the main reason it holds a competitive niche. Gastrodon also gets Sticky Hold and Sand Force, but they don't compare.
Gastrodon fills the support role. It's a special attacker with base 92 Sp. Atk. Base 39 Speed is low. Priority moves or Trick Room are the way to go. And it's enough bulk to take a hit or two.
Gastrodon appears in 13 games, including Platinum, HeartGold & SoulSilver, and Diamond & Pearl.
Gastrodon first appeared in Diamond & Pearl and has been available in 13 games across 6 generations. Obtainable through wild encounters in most titles where it appears.
- Gen IY
Yellow - Gen IRB
Red & Blue - Gen IIGS
Gold & Silver - Gen IIC
Crystal - Gen IIIRS
Ruby & Sapphire - Gen IIIFRLG
FireRed & LeafGreen - Gen IIIE
Emerald - Gen IVPt
Platinum - Gen IVHGSS
HeartGold & SoulSilver - Gen IVDPDebut
Diamond & Pearl - Gen VBW
Black & White - Gen VB2W2
Black 2 & White 2 - Gen VIXY
X & Y - Gen VIORAS
Omega Ruby & Alpha Sapphire - Gen VIIUSUM
Ultra Sun & Ultra Moon - Gen VIISM
Sun & Moon - Gen VIILGPE
Let's Go Pikachu & Eevee - Gen VIIISwSh
Sword & Shield - Gen VIIIPLA
Legends: Arceus - Gen VIIIBDSP
Brilliant Diamond & Shining Pearl - Gen IXSV
Scarlet & Violet - Gen IXLZA
Legends: Z-A