The Pikachu virus, or the Pokey Virus, was the first computer virus designed to attract children due to its incorporation of Pikachu from the Pokémon series. The virus arrived in the form of an email titled "Pikachu Pokemon" with the subject "Pikachu is your friend."
The virus that was spreading mainly through Microsoft Outlook by attaching to emails, comes with a saying: "Between millions of people around the world I found you. Don’t forget to remember this day every time MY FRIEND". The attachment file is named "PikachuPokemon.exe".
After the user activates the virus by clicking the executable attachment, the virus works by adding several lines to the "autoexec.bat" file, telling it to delete the Windows folder and the Windows/System32 folder, two of Windows most critical directories. However at the next boot, Windows prompts users asking them whether they want to delete those folders or not, rendering the Pikachu's success in deleting Windows in the user's hand.
The defect is believed to be the reason why the virus has not caused big damage.