Most unusual/mesmerizing female voice.

Always liked the ex abba singer with “there’s something goin on”
always seemed eerie to me.

 The slight echo, at 2-3 am, ripped, always was eerie to me.
 Still a great song!

Dusty Springfield
Karen Carpenter

I'm going to stick to mesmerizing.  Laura Nyro, Emma Kirkby, Judith Nelson, Yma Sumac, Janis Joplin, Kate Bush, Ronnie Spector, Billie Holiday, Maria Callas, Elizabeth Schwarzkopf, Stevie Nicks, Aretha Franklin, Patsy Cline, Elly Ameling.

To anyone not familiar with Dulce Pontes, do yourself  a favor and take a listen.  Music lives inside this woman.
https://www.youtube.com/watch?v=ztI3dJX0l8k

Bette Midler CAN/could sing. A mindblower is AM I Blue from The Divine Miss M is mesmerizing when played on a HQ system