Poliwhirl are a pokemon commonly found in lakes and rivers where humans swim. Typically, the two coexist peacefully; humans occasionally collide into Poliwhirl because of their water-like color, the Poliwhirl shrug it off and swim a little deeper next time.

Occasionally, an unfortunate swimmer dives too deep within the water and gets lost in the swirl on a Poliwhirl's stomach. Although on land the spiral must deliberately rotate to hypnotize, and even then often fails to so much as put the opponent to sleep, with a background of murky water, and with it undulating as it does when a Poliwhirl swims the white-and-black circle gains a special potency. Swimmers are taught from a young age to close their eyes when they dive underwater to avoid the Poliwhirl swirl, but occasionally one of them forgets to do so or lacks the good sense to listen, catches sight of the swirl, and falls asleep instantly.

Typically, they will drown before they wake up. Those who are rescued will unfailingly describe vivid and wonderful dreams, and will inevitably return to the water (over the desperate pleas of loved ones) to have those dreams once again.