If the signs were mythological creatures:

Aries: Werewolf
Taurus: Hell hound
Gemini: Doppelgänger
Cancer: Banshee
Leo: Fairy
Virgo: Angel
Libra: Nymph
Scorpio: Siren
Sagittarius: Ghost
Capricorn: Mermaid
Aquarius: Vampire
Pisces: Shapeshifter