Shugo Chara!

Season 1, Episode 4

Episode Title: I'm the Joker!?

Air Date: 2007-10-27

Overview:

Amu joins the Guardians as "The Joker", much to her dismay, and they inform her about the mysterious X Eggs. Ikuto tries to make amends with Amu. A mysterious new teacher named Yuu Nikaidou joins Amu's class.