Colin the Clown is a character who appeared in the episode Happy Birthday Peter!. He did a magic show and was shown to be afraid of lions. Horrid Henry and Rude Ralph scared him off by pretending a lion escaped from a zoo by using Perfect Peter's lion puppet he got as a birthday gift. Colin also has a white rabbit, which ended up eating Peter's birthday cake at the end of the episode.

In Series 3-4, he is portrayed as a mute and communicates through sounds.