A magazine article states Flutter Mane's name came from a creature in the Scarlet Book resembling a giant, aggressive Misdreavus, with some believing it to be the ghost of a long-gone pterosaur. It has the highest base Special Defense of all Paradox Pokémon, tied with Dusknoir for the highest among Ghost types, but the lowest base HP, Attack, and Defense of all Paradox Pokémon.
It was designed by Hitoshi Ariga, whose favorite Pokémon is its apparent relative Misdreavus. It may also draw on the bruxa, a vampire witch of Iberian folklore, or the similar Polish strzyga, and its winglike hair may reference Flying Heads, often shown with long hair and bat- or bird-like wings, or the Mapuche Chonchon, a sorcerer's detached head that flies using its ears.
Flutter Mane has an SVP Black Star promo illustrated by Takumi Wada, and Temporal Forces gave it a Rare illustrated by kodama. Surging Sparks added an Uncommon printing, and Prismatic Evolutions brought back kodama for a further Rare Flutter Mane.
Flutter Mane's earliest non-promo card, a Rare from Temporal Forces illustrated by kodama.
An Uncommon Flutter Mane from Surging Sparks, illustrated by Ebila.
A Rare Flutter Mane from Prismatic Evolutions, illustrated by kodama.
No, it has no evolutionary family members.
Misdreavus, along with folkloric figures like the bruxa and the Mapuche chonchon.

ハバタクカミ
Ghost · Fairy
Flutter Mane is a Paradox Pokémon, a Ghost/Fairy type with hair resembling feathered arms and red gem accents, said to float through the night sky. Our catalog lists 4 Flutter Mane cards across 4 sets, from Temporal Forces through Prismatic Evolutions, plus an SVP promo.
No published index yet — too few of Flutter Mane’s cards trade often enough to strike one.