Inspiration
In The Books of Magic, an old American Indian ghost says that everyone has a snake inside of them, which is their spine; this is the part of us that acts on instinct instead of reason.
Although the most famous human/snake chimera in Greek mythology is probably the gorgon Medusa, a more fitting one for this metaphor is Echidna, the mother of monsters, who appears human from the torso up but has the body of a snake below.
Here, then, is my 2014 Mother's Day card: a tribute to Echidna and to the human brain, where all monsters -- fictional and real -- are born.
Symbolism and Process
Coming eventually...