They’re a fey witch who changes how they look to manipulate and prank and befuddle and seduce others. Their magic is dark, illusory, spooky, and nature based.
Some thoughts:
I Want To Be Evil - Eartha Kitt
Whatever Lola Wants (Lola Gets) - Sarah Vaughan
Trust In Me (Kaa’s song from The Jungle Book)
Curveballs welcome, no wrong answers
You can’t get more witchy and gothic than Inkubus Sukkubus. Maybe Heart of Lilith? It’s not their most catchy song. Pagan Born is nice. Alternatives: Midnight Queen, Vampyre Erotica, or Aradia.
For something OG (Original Goth) maybe Spellbound by Siouxsie And The Banshees.