Go! Anpanman: Kokin-chan and the Blue Tears 2006 それいけ!アンパンマン コキンちゃんとあおいなみだ

Anpanman finds an odd little girl from outer space. The girl turns out to be Kokin-chan, Dokin-chan's younger sister who came to Earth to play. Moreover, Kokin-chan is a master of fake crying and exploits her skill to get out of the trouble she causes. And her tears have the special power to make anyone whose eyes are touched by them cry without reason.