Although the Whimsicott's remarkable control of wind is thought to have evolved to allow these pokemon to recapture their lightweight, windswept young, this is not how they primarily use this power. Whimsicott are born pranksters, and wind is their primary tool of deception and mischief. A single Whimsicott's tricks, let alone those of the species as a whole, are far too many to adequately summarize here, and pokemon trainers who face off against this pokemon are advised to prepare for literally anything. It is common to reduce anti-Whimsicott preparation to target only such common schemes as taunting opponents or using support techniques out of their apparent turn, but one should not forget that these creatures use their ability to sneak into locked houses and canny manipulations of winds to account for more poltergeist sightings in Unova than all ghost pokemon combined.
In one famous match, a Whimsicott was summoned legally, but appeared not to emerge from its pokeball, and knocked out multiple opposing pokemon while concealed in a low-lying fog cloud to the protests and bafflement of the opposing trainer. In another, a Whimsicott disguised itself as a Flaaffy with body paint, which was allowed as a held item, and shrugged off earthquakes until the opponent finally discovered the ruse.
Other Whimsicott schemes have been less successful, and Whimsicott trainers should be advised to pay close attention to their pokemon and memorize even the most obscure rules of the Pokemon League. Incidents of Whimsicott attempting to buttress pokemon's attacks while hidden outside their pokeball are commonplace, and have led to many an embarrassing disqualification. And of course, Whimsicott love playing pranks, and this does not exclusively apply to ones pulled on their enemies; opponents must be wary only in battle, but Whimsicott trainers must always be ready for trickery.
