Lake Verity/Anime

In Following A Maiden's Voyage!, and  stopped by Lake Verity while on their way back to Professor Rowan's Research Lab in Sandgem Town. At the lake, they briefly encountered a mysterious figure flying over the water's surface. Dawn would eventually learn that the figure she saw was in fact the Legendary Pokémon said to be the guardian of the lake,.

In Strategy Begins at Home!, Sayer hired to fish in the lake for  for their Goldeen Scoop booth at the Twinleaf Festival.

In The Needs of the Three!, it was explained that Lake Verity, and indeed all three of Sinnoh's lakes, are the entrances to another world where the reside, and they do not actually live in the lakes themselves. Later, a pink whirlpool appeared in the lake due to J|Pokémon Hunter J dropping the Galactic Bomb into Lake Valor. From this portal emerged Mesprit, who quickly teleported away to Lake Valor. This was witnessed by Professor Rowan and his assistants.