The Hidden Grotto
You found a hollow tree...
Games
Gen 1
Red / Blue / Yellow
Fire Red / Leaf Green
Let's Go Pikachu / Eevee
Gen 2
Gold / Silver / Crystal
Heart Gold / Soul Silver
Gen 3
Ruby / Sapphire / Emerald
Omega Ruby / Alpha Sapphire
Gen 4
Diamond / Pearl / Platinum
Brilliant Diamond / Shining Pearl
Legends: Arceus
Gen 5
Black / White
Black 2 / White 2
Gen 6
X / Y
Legends: Z-A
Gen 7
Sun / Moon
Ultra Sun / Ultra Moon
Gen 8
Sword / Shield
Gen 9
Scarlet / Violet