the elephant turning its head

while doing some patient care at bed side i noticed W has a huge tatoo on his hand. I saw it some kind of elephant...
i asked him " is it a flying elephant"
he replied " it is an elephant turning its head looking back"
What is the metaphor? i was curious.
he answered me with eager " one knows where he came from?"
....
15 min later i came back and joked with W " i don't think the elephant has no neck ... so it can't look back ".
How silly i was .