The worm was first detected in June 2000, and mainly spread in the form of an email titled "Pikachu Pokemon" [sic].

The body of the email contained an attached executable file, "PikachuPokemon.exe", which installed a worm that attempted to delete two critical directories of the user's Microsoft Windows operating system.

Pikachu is a yellow mouse-like creature[1] with electricity powers in Pokémon, a Japanese video game series and anime.

[7][8] Opening the executable showed users an animated image of Pikachu bouncing, along with the message: "Between millions of people around the world i found you.

These commands would be executed at the next boot (the next time computer is turned on[3]), in an attempt to delete two critical directories of the Microsoft Windows operating system.

[2][3] On August 24, anti-virus company Trend Micro said they had only received ten reports of the virus, and that nobody had opened it yet.

Symantec (another anti-virus company), Trend Micro, and Sophos said that the slow spread of the email gave them time to update their products to include a defense against the worm.