Happy Pets new Limited Edition "Shadow & Light Series" sports halos and horns, but unless you get a unicorn, these items are pet props that can be taken off and are not breedable traits.
Right now, the cheapest and hottest selling pets are the
Sparkling Guardian Dog and the
Hell Hound, which both go for 60 Facebook Credits (or exactly $6 USD). The Hell Hound is no
Cujo, but it's clearly blood-splattered. And there's only three of the heavenly hounds left!
Both the
Sparkling Angel Cat and
Hellcat go for 70 FB Credits ($7 USD), while the
Sparkling Guardian Unicorn and
Raven Unicorn are both 80 FB Credits ($8 USD). Of them all, the Hellcat is the least popular, with still 401 left in the store.