Sing! Purin! : Season 1 Episode 45

Entering Neon Town, a bustling Metropolis where everyone is tired and rude, Satoshi and his friends find a Purin who is too shy to sing its hypnotic song. Realizing they can kill two birds with one stone, Kasumi tries to teach the Purin to sing while the Rocket-Dan attempts to record the song so they can use it against Satoshi. Everyone falls asleep, including Satoshi and his friends and the Rocket-Dan, and a miffed Purin uses the marker hidden in her microphone to draw on everyone's sleeping faces.