Starlet

Real Name: Selena Brown
First Appearance: Moon Girl Fights Crime #7 (1949)
Original Publisher: E.C.Comics
Created by: Sheldon Moldoff

Starlet becomes Moon Girl

Origin: 

Selena Brown was an orphan girl who grew up in a farm with great fear of the moon. One night, cleaning her attic, she came upon a magic Moon-Jewel necklace which gave her incredible strength. She uses this gifts in a variety of ways that catch the attention of the media and Moon Girl.

Eventually, she winds up saving two hardened criminals from a possibly fatal accident. They, seeing the potential for crime in her, blackmail her with killing her foster parents if she doesn't help them break into a bank. She complies.

When Moon Girl intervenes, they shove her into the bank vault, where she starts suffocating. She is eventually rescued by Moon Girl, who turns out was the girl's cousin all along.

Given the secret identity of Star (called "The Starlet" in her second and final appearance), she unceremoniously joins Moon Girl as her sidekick.

Public Domain Appearances: 

Moon Girl Fights Crime #7-8