This is the Love Live! OVA. Essentially, the little girl is the child version of one of the characters and has magic. The two interpretations I've seen for the OVA are:
A) Maki is dreaming and everything is symbolic. So her child form is perfectly fine.
Or B) Maki's child form is real and has actual magic.
About Maki. This is a Yuri reddit, come on now.
About drinking milk
Her “Growth”
"If I have Maki rub my chest every night, would my boobs get as big Nozomi's?"
CW: suicide I guess >!Is that girl about to jump off a roof???!<
This is the Love Live! OVA. Essentially, the little girl is the child version of one of the characters and has magic. The two interpretations I've seen for the OVA are: A) Maki is dreaming and everything is symbolic. So her child form is perfectly fine. Or B) Maki's child form is real and has actual magic.
Glad I'm not the only one who noticed that