This is an early concept for, basically, Rarity as a sphinx. While this is kind of a spoiler, in Reverie Equestria, several major characters have had past reincarnations that may or may not be relevant to their familiar, modern incarnations. For instance, in a past life, Rarity was a queen of the sphinxes... kind of explains a lot, doesn't it.
I don't really wanna go into it any more than that right now, sorry. x)
P.S. In Friendship is Magic, sphinxes normally have the same faces as ponies. This is undoubtedly because Earth's sphinxes have human faces and "the human race" in FiM is ponies. I may or may not do an edit later with this - I'm not a big fan of that particular design element myself. My own sphinxes have kitty faces too, I just prefer them that way.
P.P.S. The proper Sekhmet has the hieroglyph for "woman", altered to be wearing the Eye of Ra, as the second character. I took the heiroglyph for "cat", edited it to resemble a sphinx - as well as actually resemble a cat because the guys with 20 cat goddesses and endemic lions and panthers apparently never saw one before - and added the Eye of Ra to that instead.