Also, in heraldry, a beast usually represented like a hind, but with cloven hooves and spangled with stars. As with all imaginary monsters, it is a bit hard to decide what their proper (natural) colour is, but pantheons proper are usually depicted purpure (purple).

Pantheons are used as supporters by the Marquess of Winchester, though they are sometimes more prosaically described as hinds semé of estoiles, that is, hinds spangled with stars. They have also been granted as supporters to the United Kingdom Atomic Energy Authority.

I'm afraid I can't tell what connexion the name has with the more familiar sense of 'pantheon'. My guess is none, and it's an alteration of 'panther'.