From Bulbapedia, the community-driven Pokémon encyclopedia.
Izabe Lake (Japanese: イザベ池 Izabe Lake) is an anime-exclusive location near the Valley of Destruction on Izabe Island in the Hoenn region.
The lake is the current resting place of an ancient stone Poké Ball containing a giant Claydol, which was said to have caused "The Great Destruction" on Izabe Island over a thousand years ago. The destruction occurred over seven days and seven nights until Claydol was finally sealed in the stone Poké Ball by a legendary white sage. Sigourney, the island's current sage, continues to watch over Lake Izabe and the stone Poké Ball to prevent the same havoc from happening again.
In Claydol Big and Tall, Team Rocket broke the stone Poké Ball in an attempt to steal the valuable Pokémon inside. However, the giant Claydol proved to be too powerful for them to control, and it went on a rampage towards a nearby village. Following Sigourney's ancient book, a beautiful maiden was required to distract Claydol. While Jessie, Meowth, and May all tried to be this maiden, Wobbuffet, disguised in a maid's outfit and playing the flute, attracted Claydol's attention. Meanwhile, everyone else levered a second stone Poké Ball and managed to seal Claydol inside once again. The Ball then rolled into Lake Izabe after Team Rocket tried to steal Claydol again.
Pokémon seen near Izabe Lake