My original tumblr post was here. This charming illustration was first posted on tumblr by The Steve Niles tumblr, which gave this account of its provenance:

Monica commissioned this awesome piece from Cat of the Frankenstein Monster and Lucy. I’m speechless right now. [Faustus: “Monica” and “Cat” contain broken or firewalled links to (yuck) Facebook]

The image comes to us via gregorysshocktheater, which added the comment “Adorable!”