Virtual

Virtuals were digital beings from another dimension. When one of their plate-sized spaceships crashed on Earth in London, the Virtuals escaped by uploading themselves onto the internet in a music file track "Alien Infiltration". As a result of mass downloading those that listened to the track (like young Rich), entered into a trance state that led them out onto the streets. The Doctor was able to delete the Virtuals from the internet server and paste it onto Amy Pond’s phone before sending them home. (DWAM: Sound Bytes)