Maybe double concave with a swallow tail.

It's like a snake swallowing its own tail.

Caroline has this great tattoo of a snake swallowing its own tail, and--

Stood with his head between his legs, and tried to swallow its own tail.

An immortal, perfect creature. A serpent eatng itself... swallowing its own tail.

Caroline has this great tattoo of a snake swallowing its own tail, and...

Caroline has this great tattoo of a snake swallowing its own tail, and--

Yeah, and it was all coiled up, trying to swallow its own tail, man.